Principles and requirements for modernization of the public telephone network. Modernization of rural telephone network
Modernization of the telephone network in the villages of the Ungheni region with the introduction of triple play services based on SI3000 Msan equipment
INTRODUCTION
In connection with the development of economic activity in the Republic of Moldova, a significant degree of population migration, the volume of transmitted information and the requirements for the quality of electronic communications have increased significantly. The transfer of information has become an integral part of any technological process, as well as a factor that significantly influences labor productivity.
Electrical communications is an industry that, due to its specificity, is interconnected with all spheres of society - industry, agriculture, culture, defense. Not a single process in the life of society can occur without the exchange of information carried out using technical means integrated into a telecommunication network.
The development policy for the communications industry is determined by the Government. It obliged the main fixed-line operator JSC Moldtelecom to increase the density of telephone coverage of the population in 2005 to 25%, and in 2010 - to 35% - on the basis of wired communications, as well as using radio access of the CDMA 2000 standard at a frequency of 450 megahertz.
Thanks to the widespread introduction of digital telephone exchanges, labor costs for the manufacture of electronic switching equipment have significantly decreased due to automation of the process of their manufacture and configuration, overall dimensions have decreased and the reliability of the equipment has increased due to the use of a high-level integration element base. The volume of work during installation and configuration of electronic equipment in communication facilities has also decreased, and the staff of service personnel has been significantly reduced due to full automation monitoring the functioning of equipment and creating unattended stations. The metal consumption of station designs has been significantly reduced, the area required for installing digital switching equipment has been reduced, and the quality of transmission and switching has improved. Auxiliary and additional types of subscriber services have been introduced.
The use of powerful microprocessors of wide application allows the use of the latest achievements of microprocessor technology. The same functional blocks are used to build stations of different sizes and purposes, which leads to a small number of printed circuit board types. This in turn simplifies equipment maintenance and reduces the volume of spare parts. Thanks to this, high economic efficiency is achieved in the range from very small to very large plants.
The principles of modularity are also used in the software architecture of digital PBXs. Modules are basically composable blocks for system design, layout, testing. They are defined regardless of their physical location. Communication between modules is carried out using internal exchange messages. The operating system ensures that messages are sent to their destination.
The goal of the diploma project is to develop a project for station facilities for the terminal station of a rural telephone network using the equipment of a digital multiservice subscriber access node SI3000 MSAN from the Slovenian company Iskratel.
The relevance of this thesis project lies in the fact that in order to improve the quality of customer service and provide TriplePlay services, it is necessary to replace existing equipment with NGN (next generation networks) equipment. Necessary requirements satisfy digital telephone exchanges built on the basis of IP, which, thanks to the method of construction and the use of modern technologies, can provide maximum effect with a minimum of operating costs.
The first chapter provides an analysis of the existing network structure, types and capacities of stations, the structure of subscriber lines, communication organization diagram, and the state of equipment in the rural area of the villages of the Ungheni region.
In the second chapter, a block diagram of the modernized network is being developed with the selection of equipment for each locality. Development of a new communication scheme. An overview of the SI3000 MSAN multiservice subscriber access node, SI3000 MSAN modules is provided, and also describes the technical data of the system, system architecture, interfaces and signaling of the digital multiservice subscriber access node SI3000 MSAN Iskratel. The load is calculated and distributed, and the required number of modules and interfaces is determined.
The third chapter shows that the proposed development is cost-effective. The following economic indicators are calculated: capital costs, current costs, expected profit, annual economic effect and payback period of capital investments.
In conclusion, brief conclusions obtained as a result of the development of this graduation project are given.
1 ANALYSIS OF THE EXISTING TELEPHONE NETWORK. MODERNIZATION OF A NETWORK FRAGMENTON THE BASETECHNOLOGIESNGN
1.1 general characteristicsUnghenskydistrict
Ungheni district is located in the western part of the Republic of Moldova on the border with Romania. The eastern border of the region is 70 km from the capital of the republic - Chisinau. The district includes 74 settlements: 72 villages and 2 cities, Ungheni and Cornesti. The relief is represented by hilly steppe. The population is 110,700 people, of which 75,500 are rural residents, 38,000 live in the regional center - the city of Ungheni.
Below are data on the administrative center of the district - the city of Ungheni:
Geographic coordinates 47°12′15″ N. w. 27°47′45″ E. d.
Located on the Prut River, 107 km from Chisinau, 85 km from Balti and 45 km from Iasi. In Ungheni there is a customs office on the border with Romania. Ungheni railway station is a border station between the railways of Moldova and Romania. The Prut River flows through the city from northwest to southeast, which flows into the Danube River bed and then into the Black Sea. The main buildings of the settlement are located within the city and it is conventionally divided into several microdistricts: Center, Molodezhka, Danutseny, Biokhim (within the biochemical plant), Bereshty, Vasilika.
The area of the entire territory is 16.4 km 2 .
Population - 38,000 people (2010). The absolute majority of the population by nationality are Moldovans (more than 3/5); Ukrainians, Russians, Jews, Romanians and Gypsies also live.
Annual city budget ~ 25 million lei.
Expenditures in the field of preschool and secondary education - 15 million lei.
Heating costs - 5 million lei.
Other expenses - 1-2 million lei.
1. 2 general characteristicsvillages proposed for network modernization
The proposed modernization covers four villages of the Ungheni region: Agronomovka, Todiresti, Petresti, Simeni.
In all the above-mentioned settlements, the population is engaged in agriculture: viticulture, winemaking, gardening and growing grain crops. Most of the population of the villages of Agronomovka, Todiresti, Petresti and Simen find work in the city
Earth inside settlements divided among former collective farmers into quotas, which allows each resident to cultivate the land independently, grow the necessary agricultural products on it and then sell them, and this, in turn, allows small private businesses to develop. With the development of private business, the population of these villages is in great need telephone communication and innovative technologies.
Also, nowadays a personal computer is far from a luxury even for a peasant.
Many residents of these villages left the Republic of Moldova in order to find higher earnings. Traffic on incoming and outgoing long-distance and international communications has increased significantly.
In general, the financial condition of the population has improved in recent years, free funds have appeared, which a potential subscriber is ready to invest in installing a telephone and connecting to broadband Internet access. Based on the above, there is a need to develop a next generation network.
To predict the capacity of stations based on the number of residents, it is necessary first of all to forecast the population in these settlements. According to the data of the National Bureau of Statistics of the Republic of Moldova, we have the following population indicators for January 1, 2009 and January 1, 2010 (see Table 1.1). Based on these indicators, the population growth rate is 1.06. Using this coefficient, we can predict what the number will be in the next 5 years.
Table 1.1– Data on the population of villages proposed for modernization, and population forecasts for 2015.
|
Us. paragraph |
Number of inhabitants |
Number of inhabitants |
Forecast. Number of inhabitants 2015 |
|
|
v.Petresty |
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|
v.Todireshti |
||||
|
Agronomovka village |
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1.3 Brief description of the existing telephone networkin the direction of villages and the regional center.
The simplified block diagram (Figure 1.1) of the Ungheni regional telephone network shows terminal (rural, for which design is underway) and central (city) telephone exchanges. The lines between the end and central stations indicate connecting lines (CL), organized via a fiber-optic transmission system based on Tellabs equipment, using STM - 1 flows. Next to the symbol of the telephone exchange is the name of the locality where it is located, the type of telephone exchange, its installed capacity and range of numbers used. Figure 1.1 shows the structure of the telephone network in the direction of Ungheni and the villages included in the modernization project, where SI2000 telephone exchanges manufactured by ISKRATEL, Slovenia were installed. These stations are devices using the principle of channel switching, and support almost all used signaling for interaction with the PSTN network. This fact makes them extremely convenient for use on networks where stations from different manufacturers are present. However, in order for telephone companies to successfully compete in the communications services market, they must constantly introduce new ranges of services for which, at the moment, the scope of classical telephony is narrow. That's why most phone companies are upgrading existing networks, placing the main emphasis on their adaptation to data transmission at speeds sufficient to provide services such as video telephony, IP-TV, high-speed Internet access, etc. etc. Manufacturers, in turn, are meeting the needs of telephone companies halfway, developing equipment that makes upgrading smooth and cost-effective. Such developments are also being carried out by ISKRATEL, the result of which, at the moment, is the SI 3000 MSAN platform. It can be used at all stages of modernization, from parallel operation on a channel and packet switching network, to a complete transition to a new generation network - NGN.
| Discipline: | Communications, communications, digital devices and radio electronics |
| Type of work: | graduate work |
| Language: | Russian |
| Date added: | 30.08.2010 |
| File size: | 1243 Kb |
| Views: | 3014 |
| Downloads: | 22 |
| Features of the digital switching system "Kvant-E". Bandwidth of the switching field. Connecting lines and interactions between stations. Characteristics of reliability of equipment of the CSK "Kvant". Features of the organization of subscriber access. | |
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This diploma project examines the issues of modernizing the telephone network of the village. Uryupinka Akkolsky RUT Akmola region. The project analyzed the current situation of the network and selected equipment. CSK “Kvant” (Russia) was chosen as the optimal equipment.
The existing local cable network was reconstructed and the problem with interstation lines was resolved.
The project also calculated the main indicators of high-quality network operation, as well as technical and economic indicators. Developed engineering solution in life safety and ecology.
- INTRODUCTION -
It is generally accepted that the development of telephone communications in the world began in 1876, which was marked by Alexander Graham Bell receiving a patent for the invention of the electromagnetic telephone. From the history of technology development it is known that similar inventions were made long before 1876. But for a number of reasons, these developments were not officially registered. Following the generally accepted norms of patent science, Alexander Graham Bell is considered the discoverer of telephone communication.
The term "Telephone network" is interpreted as a secondary network intended for the transmission of telephone messages. The public telephone network (PSTN) has an unambiguous name - Public Switched Telephone Network (PSTN). Depending on the level of the hierarchy of the VSS of the Republic of Kazakhstan, international, long-distance, intra-zonal and local telephone networks are distinguished.
Telephone exchanges and telephone nodes are used as switching equipment on the PSTN. A telephone exchange (only automatic telephone exchanges - PBX will be considered below) is a switching station that connects subscribers to the PSTN. A telephone node is a switching node designed to establish transit connections on the PSTN.
The need to develop new principles for constructing telecommunication networks arises, as a rule, with the advent of each new generation of information transmission and distribution technology. For telephone communications, the introduction of digital transmission and switching systems is a typical example of such a process.
The interconnected communication network (ICN) of the Republic of Kazakhstan in the early 90s entered a phase of significant qualitative changes due to widespread implementation digital technology - transmission and switching. Urban (GTS) and rural (STS) telephone networks undergo the most significant changes during the digitalization of the RK WSS.
Primary and telephone networks in rural areas have a number of scientific features. SPS resources are usually used for wire broadcasting, telegraph communications, organizing leased lines, and the functionality of STS is used for building intra-industrial telephone networks (IPTN), dispatch telephone networks (DTN) and other attributes of the management system of former collective and state farms. These reasons served as the basis for the creation of another guiding document - “Principles for organizing telecommunications in rural areas.”
When developing the basic principles of construction national system It is advisable for telecommunications organizations to carefully review relevant international recommendations and standards. We can list several reasons confirming the validity of this statement: firstly, only compliance with the mentioned recommendations and standards will ensure reliable and high-quality international communications, which any country seeking integration into the international community needs; secondly, these recommendations and standards represent the results of the work of international research centers, such as, for example, SSE and ETSI; it is hardly wise not to use the potential they have created; thirdly, neither the use of imported nor the export of domestic equipment is possible without making appropriate adjustments to the hardware and software of telecommunication equipment to harmonize its basic characteristics and the requirements of the national network.
In this thesis project, taking into account the above conditions and requirements, the issues of modernizing the telephone network of the village are considered. Uryupinka Akkol RUT Akmola region. The KVANT-E switching system was chosen as the PBX.
This switching system was known in the form of quasi-electronic telephone exchanges (they were created by decision of the military-industrial complex in the 70s). In 1989, the second generation of automatic telephone exchanges “KVANT” was developed, already digital under the code name “KVANT-SIS” (reference and information services).
Since 1995, production of the next - third generation of automatic telephone exchanges KVANT - began in Euroconstructive. With each generation, the technical and operational performance of the vehicle has improved. Example: PBX KE 2048 NN - 25-30 cabinets, 1.5 W/N; ATS E SIS 2048 NN - 10-12 cabinets, 2.0 W/N; KVANT E (1996) 2048 NN - 3 cabinets, 0.6 W/N; KVANT E (1998) 2048 NN - 2 cabinets, 0.5 W/N.
Currently, the system is produced by the following development companies: Kvant-Intercom (Riga, Latvia); Kvant - St. Petersburg (St. Petersburg, Russia). Manufacturers: GAO VEF (Riga, Latvia); JSC IMPULS (Moscow, Russia); JSC SOKOL (Belgorod, Russia); Automation Plant (Ekaterinburg, Russia); TEST plant (Romny, Ukraine); TA Plant (Lvov, Ukraine); FTZ (Blagoevgrad, Bulgaria).
In addition to replacing the automatic telephone exchange during the modernization of the telephone network with. In Uryupinka, the local cable network has been expanded, the distribution system with interstation communication lines has been replaced.
1 . Analytical researchIon the topic of design and development for their technical implementation
1.1 Geographical and economic features of the region
The Akmola region, located in the center of Eurasia, borders on several regions of Kazakhstan and is today one of the large investment-attractive regions of Northern Kazakhstan. Having unique natural resources - chromite, copper-zinc, gold-containing, nickel-cobalt, titanium-zirconium ores, combined with an advantageous geographical location and availability of transport and communication systems, the region rightfully deserves special attention investors. Evidence of this is the foreign and joint ventures successfully operating in our region, representing the interests of companies from such countries as China, the USA, Great Britain, Germany, Turkey, Spain, etc. The level of technology and intellectual potential of the region meets modern market requirements and is capable of mastering new types products. The capital of the Republic of Kazakhstan, Astana, also plays an important role in the development of the region.
Our region offers the opportunity for investment and development of such industries as: mining, manufacturing and light industry, energy, metallurgy, mechanical engineering, agriculture.
Akmola region, occupying a favorable geographical position, has a developed network of transport communications. Railways with large junction stations connect important directions north with south, west with east.
In 2006, Akmola region achieved good rates, both in the real sector of the economy and in the social sphere. In 2006, a positive character economic development has been preserved, as evidenced by the increase in the production of goods and services in almost all sectors and spheres of the economy, the growth of investments in fixed capital, moderate inflation rates, and the continued growth of real incomes of the population and domestic consumption. Compared to 2005 and 2004, industrial production increased by 16.2%, incl. in the mining industry the growth was 24%, in the manufacturing industry - 2.6%. In 2006, industrial products were produced in current prices in the amount of 273.7 billion tenge. The index of physical volume of production compared to 2005 amounted to 116.2%. Product volume Agriculture in all categories of farms was estimated to be 26.5 billion tenge and decreased by 7% compared to 2005, which is due to the low harvest compared to last year. In 2006, 138.5 billion tenge of investments in fixed assets were used for the development of the economy and social sphere, which is 14.7% more than in the previous year.
The Akkol district considered in the diploma project is located in the southern part of the Akmola region. Formed in 1928. The area is about 6.9 thousand km². Population over 30 thousand. Average population density 5.6 people.
per 1 km².
On the territory of the Akkol region there are 9 rural and 1 city administrations. Administrative center of the district - Akkol city. The terrain of the territory is flat and shallow. Soils: southern chernozems, clayey and loamy in combination with solonetzes. The climate is continental, arid. The average annual precipitation is 300-350 mm. The area is rich in water resources such as the rivers: Talkara, Aksuat, Koluton; lakes - Zharlykol, Itemgen, Shortankol, Balyktykol.
There are about 20 industrial enterprises, 10 construction and transport organizations in the Akkkol region. Medium and small businesses are developing. The area of agricultural land is 567.0 thousand hectares, including arable land 226.0, pastures 318.5 thousand hectares. The district mainly grows and exports wheat.
There are 39 preschool institutions in the region, 34 secondary schools, children's music school, Schoolchildren's House, PTSH-10, 24 clubs, 4 Houses of Culture, 39 medical institutions. A regional newspaper is published. A railway passes through the territory of the Akkol region. Astana-Kokshetau - Makinsk, highway Akkol-Astana and others.
On the territory of the district there are: Akkol marble deposit, Akkol crushed stone plant, Akkol forestry enterprise, Granite deposit, mechanical repair plant and other organizations.
The population according to statistics is: in the city - 16,110 people, in villages - 15,837 people. The area is experiencing population growth.
1.2 Brief description of the telecommunications sector
As of November 10, 2006, the Akkol regional telecommunications networks had 4,774 GTS and STS subscribers, with an installed station capacity of 4,674 numbers. In the city telephone network, the station capacity involved is 90% (2520 numbers). Since 2004, SI-2000 has been in operation as the CA of the Akkol RUT.
Rural telephone networks of Akkol RUT consists of nine rural terminal stations (OS) of various types, as well as a central station (CS) (Figure 1.1).
As of November 10, 2006, rural networks were used at 94.8%, with an installed station capacity of 1,974 numbers, 1,888 numbers were used, mainly for residential sector subscribers. ATSC 50/200, M-200, Kvant-E are used as end stations (OS). All rural subscribers are provided with access to long-distance and international communications. At rural stations where ATSC 50/200 is operated, modems are installed for constant monitoring of operation.
Figure 1.1 - Communication organization diagram of Akkol RUT
In the Akkol region, work is constantly being carried out to reconstruct and modernize the telecommunications sector. For example, work on preparing premises for a new electronic station, switching subscribers of an existing station in populated areas (ATSK 50/200 to digital), analog equipment for ICM-30 equipment, telephone installation in villages where there are no automatic telephone exchanges, etc.
For 2005 - 2007, it is planned to further modernize rural telephone exchanges ATSC-50/200 to electronic ones in other settlements. For the second and third quarters of 2007 and early 2008, it is planned to repair and reconstruct the line cable facilities in all rural settlements to further increase the number of subscribers.
It is planned to prepare new premises for automatic telephone exchanges in villages. To improve the performance of connecting lines between the central station and the OS, it is planned to overhaul cable lines in the villages of Priozernoye, Iskra, and Trudovoye. Summary information on the state of STS telecommunications (Table 1.1).
From Table 1.1 it can be seen that in the area under consideration. Uryupinka is operated by ATSK-100/2000 and LVK-12 as channel-forming equipment. These systems are not currently produced by the manufacturer, which is why there is no repair base. Along with physical wear and tear there is also moral wear and tear.
Table 1.1 - Summary information on the state of STS telecommunications
Name | Name settlement | switching | Mounted capacity, numbers | Transmission system | guide | Distance from CS-OS, km | Note | ||
Akkol | S I-2000 | ||||||||
OS-1 | KSPP 1*4*0.9 | connected to OS-1 s. Stepok with RSM-11 | |||||||
OS-2 | Novorybinka | KSPP 1*4*0.9 | connected to OS-2 s. Kalinino and s. Kurlys with direct numbers | ||||||
Labor | KSPP 1*4*0.9 | connected to OS-3 in the village of Podlesnoe and the village. Kirovo with direct numbers | |||||||
KSPP 1*4*0.9 | |||||||||
Naumovka | KSPP 1*4*0.9 | connected to OS-5 s. Vinogradovka and the village of Ornek, village. Filipovka direct numbers | |||||||
Uryupinka | ATSC100/ | VLS BSA (4mm) | connected to OS-6 s. Amangeldy and the village of Erofeevka, village. Maloaleksandrovka with direct numbers | ||||||
Priozernoe | KSPP 1*4*0.9 | connected to OS-7 in Lidievka village with direct numbers | |||||||
Ivanovskoe | VLS BSA (4mm) | ||||||||
ZKBP 1*4*1.2 |
Note: Apart from the above, not villages with telephones (Table 1.1): Maly Barap, Krasny Gornyak, Kzyl-tu, Kenes, Radovka, Krasny Bor are directly connected to the CS and have direct numbers.
1.3 Comparativegradecharacteristicsmodernswitching systems
Digital switching systems are more efficient than single-axis spatial systems. The main advantages of digital telephone exchanges: reduction in overall dimensions and increased reliability of equipment through the use of element base high level integration; improving the quality of transmission and switching; increasing the number of auxiliary and additional services; the possibility of creating integrated communication networks based on digital automatic telephone exchanges and digital switching systems, allowing the introduction of various types and services of telecommunications on a unified methodological and technical basis; reducing the amount of work when installing and configuring electronic equipment in communication facilities; reduction of maintenance personnel due to full automation of equipment operation control and creation of unattended stations; significant reduction in metal consumption of station designs; reduction of space required for installation of digital switching equipment. Disadvantages of digital telephone exchanges: high energy consumption due to the continuous operation of the control complex and the need for air conditioning.
Features of digital switching devices with pulse-code modulation (PCM) signals: processes at the inputs, outputs and inside the devices are coordinated in frequency and time (synchronous devices); digital switching devices are four-wire due to the peculiarities of signal transmission over digital systems.
In a digital switching system, the switching function is performed by a digital switching field. All processes in the switching system are controlled by the control complex. Digital switching fields are built according to the link principle. A link is a group (T- (time-time), S- (space-space) or S/T-) stages that implement the same function of converting the coordinates of a digital signal. Depending on the number of links, two-, three- and multi-link digital switching fields are distinguished. (C) Information published on the site
General characteristics widespread digital PBXs are listed at the end of the explanatory note in Table 1 [P.A.].
As rural PBXs (TS, US, OS, UPS), digital PBXs from Iskatel (SI-2000), MTA (M-200), Netash (DRX-4) and others have become widespread in our Republic. In this graduation project, we will consider in more detail the characteristics of the DTS-3100, DRX-4 and KVANT-E systems.
Digital telephone exchange type DTS-3100. This system is a powerful and flexible digital electronic switching system for Kazakhstan communications networks. It meets all modern requirements. Thanks to the use of modern technologies of microcircuits, computers, software and, above all, interconnection and services. DTS-3100 can be used for rural low-capacity station and for local or hub - long-distance station large capacity.
The modularity of hardware and software allows it to adapt to any network conditions. New technologies can be applied to the DTS-3100 without changing the system structure.
The concept of building a switching system DTS-3100 is open structure, providing flexibility and modularity. With the introduction of this concept, expansion and modification of the system is facilitated and can easily be combined with technological developments. The most important aspect is the implementation of the independent system structure technology. This means that advances in computer and semiconductor technology have an impact on the digital switching system. This will affect not only the production of communication equipment, but also the management of use. The solution to this is to introduce functional modularity.
All function modules in the DTS-3100 are designed on an open basis to ensure easy integration of new functions. The signaling method between functional modules is standardized. A number of functional modules form a subsystem.
Key goals in the development of the DTS-3100: flexibility to accommodate new features; ease of system expansion and preservation of price lines; large capacity, applicable to large cities; adaptation to different territories (urban or metropolitan); high efficiency and reliability; facilitating the use of software.
In terms of its distinctive features, it can be said that the DTS-3100 system provides diverse and versatile features that meet all the requirements of modern switching network: wide range of applications; great opportunities; multiprocessor structure; parallel operating system; programming language CHILL/SDL; database management system; redundancy configuration.
Technical data. DTS-3100 has found application as a telephone exchange: local switching; nodal switching; intercity switching; digital network of integrated services.
DTS-3100 system capacity: terminal subscriber load - no more than 120,000 lines; terminal inter-station load - no more than 60,480 lines; traffic capacity - maximum 27,000 Earl; call conduction - no more than 1,200,000 calls in CHNN.
Capacity of the remote access switching module: traffic capacity - more than 20 Earl; terminal subscriber load - no more than 8,192 lines; call conduction - no more than 100,000 call attempts in CHNN.
Alarm link OKS 7 - no more than 128 links.
PCM transmission interface: 2.048 Mb/s (PCM-30 system) according to CCITT recommendations G. 732, G. 711; 1.544 Mb/s (PCM-24 system) according to CCITT recommendations G. 733, G. 711.
Processor - MC 68030. Programming language - C++, CHILL, Assembly.
Rack size (width x depth x height): 750 5502.140 mm.
Power: 48V (42V to 57V) DC.
Power consumption - 0.85 W/line.
Operating environmental conditions: relative humidity - 20% - 65%.
Terms of Use. Subscriber line: line resistance: no more than - 2,000 Ohms; insulation resistance: no less than 20,000 Ohms.
Broadcast characteristics:
a) insertion loss (nominal loss): digital to digital - dB: 0; analog (2W) to digital - dB: 0; analog (2W) to analog (2W) - dB: 0; (Actual losses will depend on relative national levels); b) Crosstalk: between two lines - dB: 67 (1100 Hz reference, 0 dBmO); c) Return loss: Four wires: 16 dB (300 to 500 Hz, from 2500 to 3400 Hz) against network balance; 20 dB (500 to 2500 Hz) versus network balance. Two wires: 14 dB (300 to 500 Hz, 2000 to 3400 Hz) vs. 600 ohms; 18 dB (500 to 2000 Hz) vs. 600 Ohm; d) noise: measured noise - dBmO:< 65; неизмеренный шум - dBmO: < -40;д) уровень ошибок ᴨȇредачи: цель < на один канал.
DRX-4 system. The DRX-4 electronic station is a digital automatic system switching intended for small settlements, urban areas and enterprises as terminal, hub, central rural telephone exchange, city substation and institutional-industrial telephone exchange and complies with international ITU-T standards.
The station supports outbound incoming and backhaul communications using standard local telephone network signaling and corporate telephone network signaling systems.
Thanks to the modular architecture and the benefits digital technology A switching station based on DRX-4 implements the most optimal technical solution in specific conditions.
Support for multiple types of trunks and signaling makes it easy to fit the station into your existing environment. The communication channel with the upper-level PBX can be a digital stream transmitted via RRL, fiber-optic or copper cable, or an analog line.
In place of the central station, DRX-4 can successfully replace ATCK100/2000 stations by connecting directly to the automatic telephone exchange. At the same time, in addition to servicing communications within the region, access to the intrazonal and intercity networks is provided. In this configuration, the station can make automatic connections or connections with the participation of a long-distance operator.
The DRX-4 system is a digital PBX with distributed microprocessor control. The system has software control and a distributed structure of processor buses. Distributed control is supported through high-level control data communications protocols, transmitted at speeds up to 2.048 Mbps over redundant control buses.
The microprocessors of the MXC and DTC boards, operating at a frequency of 16 MHz, with the help of a control bus, ensure the implementation of all the necessary functions of their module with a capacity of up to 160 analog subscriber lines and 60 digital trunks. These boards provide fast loading its main software into RAM from the control and operation workstation terminal.
The DRX-4 system does not require ventilation or special conditions operation. To install a full tank system, an area of 18 m2 is sufficient. The system's power supply is fully provided by a complex key-type KEBAN installation, with 30 A rectifier redundancy based on the n + 1 principle, overvoltage protection and a battery charging circuit.
The structure of the DRX-4 software is multi-functional and multi-tasking, allowing parallel execution of many tasks. Real-time mode ensures that processes are activated and queued in accordance with the priority mechanism. Processes use object-oriented structures; therefore, any communication between processes is ensured by a precisely defined method of data transfer. Real-time tasks and data are processed by highly integrated 16-bit processors. The software for the station's control processors is written in ASSEMBLY, C++, and Visual Basic languages.
DRX-4 equipment ensures operation on rural telephone networks with a closed numbering system, open without an exit index, open with an exit index, with mixed five-six-digit and six-seven-digit numbering. Characteristics of the DRX-4 system are given in Table 1.2.
ATS of the KVANT-E system. "KVANT" is a modern, reliable, economical and constantly improved digital switching system (DSS) with a flexible modular structure of equipment and software (software), developed by KVANT-INTERKOM. It is intended primarily for the development of telecommunication networks in rural administrative regions (RAR). The system can be used locally in a rural administrative region, as a district automatic telephone exchange (RATS), a central station (CS) or a rural-suburban node (USP) of a regional center, a hub (US) or terminal station (OS) in a rural area. However, a rational option is the comprehensive implementation of the CSK "Kvant" in the SAR, in which, thanks to the presence of remote switching and subscriber modules, the system simultaneously covers with its equipment all levels of the network hierarchy of the rural administrative region, forming an overlay digital network with centralized technical operation.
Table 1.2 - Characteristics of the DRX-4 system
Maximum subscriber capacity | Up to 4000 subscriber lines (ORKH-4S-up to 300 subscriber lines) | |
Capacity per cabinet | Up to 596 subscriber lines | |
Maximum number of remote concentrators and their capacity | 2 x 500 subscriber lines | |
Maximum number | ||
Analog trunks | ||
Digital trunk lines | ||
Number of digits analyzed | ||
Maximum number of routing directions | ||
Digital seams | 2 Mbit/s and 8 Mbit/s (electrical and optical interfaces) | |
Analog trunks | 2, 4 and 8 wire type E&M; 4-wire trunk lines with in-band signaling 2600 Hz, 2100 Hz, 600 Hz/750Hz (departmental signaling) | up to 0.17 Earl |
Number of call attempts in CHNN | ||
Power consumption | 0.7 W/port | |
Operating temperature range |
On city telephone networks (GTS), using the digital switching system "Kvant" you can create an overlay digital network or digital "islands", using the system as reference stations (TS), transit stations (TS) and support-transit stations (OPTS) practically any capacity and centralizing the technical operation of the corresponding network fragment. The use of remote switching modules as substations (SS) and remote subscriber line units (BAL) as concentrators dramatically reduces the cost of a subscriber line (SL) network.
On departmental networks, CSK "Kvant" can be used both as autonomous institutional and production automatic telephone exchanges, and to create branched digital networks with centralized technical maintenance and any required topology (multi-connected, radial, tree, mixed), while providing departmental subscribers with a wide range of various technical services.
The possible capacity of stations of the Kvant-E system is determined by the modular structure of the automatic telephone exchange, as well as the required ratio between the number of AL and SL. A minimum capacity station is formed from one switching module. (C) Information published on the site
Depending on the configuration of such a station with BAL units, its capacity ranges from 100 AL (one BALK) to 2048 AL and up to 420 external communication lines.
The use of a multi-module structure makes it possible to create stations with a capacity of up to 30 thousand AL. UKS 32x32 blocks of ten CMs form a digital switching field (DSF) of a reference transit station, containing links A and B of space-time switching. Group paths (GT) ᴨȇstraps (P) in the field of link B of each UKS are evenly distributed, in twos, over the remaining UKS of link B and are used for communication between modules of link A and for transit connections between trunk bundles connected to the central communication center.
Connections in a digital switching field pass, depending on the direction, through different number links: communication between subscribers of one CM - through link A; different CM - through links A-B-A; external connections - through links A-B; transit connections of the trunk line of one CM - through link B, trunk lines of different CMs - through two links B-B.
Switching modules based on the newly developed UKS-128 units will make it possible to build medium-capacity stations more economically than UKS-32, as well as create OPS (Reference Station), OPTS (Reference-Transit Station) and TS (Transit Station) almost as large as desired containers.
The procedure for increasing station capacity or connecting new communication directions during operation does not require reconfiguration of existing equipment and long-term interruption of call service. All necessary connections and their activation is feasible in the time interval from 24.00 to 5.00.
1.4 Selecting the optimal PBXand problem statement
Comparing common specifications various systems, as well as the architecture and capabilities of three common systems (DTS-3100, DRX-4 and KVANT-E), we select the most optimal one. Criteria in in this case is an affordable price, suitability in rural networks, provision of modern communication services, etc. For this graduation project, the most economical and optimal is Kvant-E from KVANT-INTERKOM.
The digital switching system "KVANT" has a modular design, geographically distributed switching, decentralized software control and the ability to centralize maintenance. The modular architecture of the "Kvant" switching system and the presence of a two-stage hierarchy of remote locations (reference station - remote switching module - remote subscriber module) make it possible to distribute system equipment throughout the city or rural administrative region, forming an overlay digital network or digital "island" of almost any required configuration and tanks with the organization of central heating of all equipment of the Kvant system.
This project proposes the modernization of the telephone network in the village. Uryupinka, Akkol district, Akmola region. Planned modernization of the telephone network. Uryupinka, Akkol district, Akmola region creates the preconditions stable growth intercity and international traffic, provision of high-speed services, data transmission and rental of digital channels.
Modernization of the telephone network. Uryupinka is necessary to eliminate all shortcomings in the operation of the telecommunications network, which will affect the increase in the number of subscribers, bring stable financial growth to the operator, will additionally increase the markets for the provision of telecommunications services, and accordingly increase cash flow.
Timely replacement of the analog communication system with an electronic PBX and expansion of the market for the provision of telecommunications services will ensure significant superiority in competition with companies that provide similar services today.
The main goals of this project are: meeting the demand for the installation of a user terminal; expanding and strengthening the operator’s position in the communication services market; avoiding the loss of potential consumers of communication services; increasing the operator's cash flow.
The main objectives of achieving the implementation of this project are: replacement of the morally and physically obsolete station ATSC100/2000 with a total installed capacity of 500 numbers and an operational capacity of 489 numbers, the percentage of utilization of which is 86.2%, with a modern PBX with a capacity of 1000 numbers with an expansion of station and line capacity by 500 numbers, which will significantly improve the quality of services provided and accordingly increase outgoing traffic; ᴨȇreferring existing subscribers to the new PBX, building a distribution network for new subscribers.
The basis of the project strategy is to satisfy the demand for the installation of a subscriber terminal, gain a leadership position in the provision of telecommunications services, expand the market, providing consumers with. Uryupinka has the most modern, high-quality communication services.
To achieve the set goals and objectives, in meeting the demand for the installation of a subscriber terminal, the project proposes to carry out timely reconstruction of the communication line in connection with the replacement of an analogue PBX with a PBX.
2 . Peculiaritiesdigital systemswitching "Kvant-E"
2.1 Digital switching system architecture« Quantum»
The general architecture of the Kvant system is presented in Figure 2.1. It is based on the following main elements: switching modules (CM); subscriber line blocks (BAL); modules for interfaces with connecting lines (SCT, KSL); technical operation module (MTE).
The KM switching module consists of a universal switching system (UCS) and a control device (CU). The UKS includes: a space-time switching unit with a capacity of 32 or, in the future, 128 32-channel PCM lines (UKS-32 or UKS-128) and the corresponding signal, generator and control equipment.
The UKS block makes non-blocking connections of any channels of any PCM group paths (GT) connected to it.
Switching modules are grouped to build a reference, transit or reference-transit station of the required capacity, or are moved to places where subscribers are concentrated. An external CM (VKM) can be single or multi-module and contains the CM itself, BAL units and the SCT interface module with digital trunk lines. Such a remote switching module autonomously manages connections and is an independent station in the network structure, remaining, however, part of the Kvant switching system due to the use of a digital in-system signaling protocol and the possibility of control from the technical operation center (TOC) of the system. Some options for grouping CMs to build a medium-capacity station or a multi-module remote switching module are given in Figure 2.1. The choice of a specific configuration is made during the design, and options with more than three links for connections within the station are immediately excluded.
Blocks of subscriber lines BAL-K - for 128 AL with a concentration of 4:1. Production of BAL-256 has already been established. The block is included in the CM switching field by a PCM group path (GT), does not provide for the closure of an internal message and performs a standard set of BORSCHT functions for subscribers.
If it is necessary to connect paired telephone sets and/or payphones to the BAL, TEZs with kits for connecting paired PSAM devices and PTAM payphones are installed in the BALK cassette. TEZ PSAM is designed for eight ALs with TAs paired through a blocker. TEZ PTAM serves eight AL payphones, providing them with serviceability control and voltage reversal when the subscriber answers. All additional sets of PSAM and PTAM are included between AL and AK. The reference station or remote switching module can include remote subscriber modules (VAM) based on BALK ATS-200 and ATS-100.
ATS-100 can also be used as an independent station with a capacity of up to 128 numbers, having several directions of external communication via PCM lines or via physical or compressed trunk lines with a ten-day or multi-frequency code. It is possible to combine two BALK units into one ATS-200 up to 256 AL in one design. At ATS-100 (ATS-200) internal load closure and transit connections between trunk lines are provided.
Figure 2.1 - Architecture of the digital switching system "Kvant"
Interface modules with connecting lines:
SCT - for digital, BALK with CSL for physical lines and for lines equipped with frequency division distribution systems (SP). Each module occupies a cassette. SCT modules allow the use in external and internal (i.e. to VKM and VAM) communication directions of trunk lines with time division of channels (TDC) - up to sixteen joints with group PCM paths (SGT) with a transmission speed of 2048 kbit/s per one SCT. Instead of any SGT 2048, it is possible to connect SGT15 to work with PCM-15 systems with a transmission speed of 1024 kbit/sec. Connecting analog trunk lines to a digital switching system is not recommended, but if such a need arises, the CSL modules provide interface with any types of trunk lines possible on the network.
The technical operation module includes one or more computers and, if necessary, additional external input, output and information storage devices. In its minimum configuration, the MFC is installed at each station as its control center. It is possible to use MFC as a digital power station of a digital network fragment built on the basis of the equipment of CSK Kvant.
The basis of the MFC is a technical operation computer (KTE) type IBM-386 or higher. It is connected via RS 232 joints to the control device of the station where the MFC is located, and to external devices - magnetic disk drives, a printer, video terminals of additional workstations. To communicate with control devices of remote switching modules and with an external technical operation center (ETC), KTE uses dedicated data channels and modems that provide an X.25 interface. After the implementation of SS No. 7 in the Kvant digital switching system, it will be possible to replace X.25 channels with SS No. 7.
KHPP automatically or according to operator directives manages diagnostics and reconfiguration of equipment, measurements of load parameters, electrical measurements parameters of conversation paths and accumulation of the corresponding statistical information. In addition, KHPP charges all calls, processes alarm data and displays them on the display and printer. Using CTE, the operator can correct the system data of different CMs. On the digital network built on the basis of the Kvant CSK, the main station's KTE plays the role of a technical operation center (TOC). In this case, all other stations and remote modules of the "Kvant" system are serviced by a control and corrective method, without the constant presence of personnel.
2.2 Switching field capacityand control system performance
The Kvant digital switching system provides the ability to connect AL and SL (channels) with an average usage per busy hour (BHH) of 0.2 to 0.9 Erl.
The configuration of the station switching field is given at the end of the explanatory note [P.B].
In this load range (LON), there are practically no losses due to occupancy or unavailability of all possible paths for establishing the required connection in the digital switching field. The high throughput of the central communication center is due to the use of non-blocking UCS and large bundles of channels, multiples of thirty, between individual UCS. In particular, for the switching field of the automatic telephone exchange in Figure 2 [P.B.], the losses will not exceed 0.001 when switching on AL and SL with maximum load parameters. The rate of losses in the central communication center due to the inability to establish a connection from a specific input (channel) to the required communication direction (in group search mode) or to the required output (channel) in linear search mode is set equal to 0.001 and 0.003, respectively. This corresponds to the field capacity of a single-module station or remote switching module of 900 Earl.
At CSK "Kvant" each CM has his own control device, i.e. The control system is decentralized and its performance increases simultaneously with the increase in the capacity of the digital switching system. The control devices of individual CMs operate independently, interacting when servicing calls using intra-system signaling channels (ISSC). The performance of an individual CU (Control Unit) is determined mainly by the type of processor of an IBM-compatible computer.
Assuming that at the station the AL and CO loads are on average approximately equally divided into outgoing and incoming, and the average duration of one session is about 100 s, the number of calls arriving at the station from one AL and CO with maximum use of all AL and CO is on average 3.6 and 16.2 calls/hour. Taking into account the possible uneven distribution of AL and trunk loads into outgoing and incoming ones, as well as a possible decrease in the average duration of a session, the number of calls that must be serviced in the CHN with a guarantee of no overload of the control system is set equal to 5Nal + 20Ncl, where Nal and Ncl are the number of connected AL and SL.
The computer-based control device can service up to 100,000 calls/hour, which ensures the absence of overloads in any combination of the number of AL and CO lines.
2.3 Connectinglines and interaction between stations
The Kvant digital switching system provides different types of trunk lines. In-system trunk lines, as well as trunk lines to digital PBXs and PBXs of other types can only be digital. Lines to analogue stations must be digital as a rule. Their use, in comparison with analog trunk lines, increases the reliability and quality of transmission paths, simplifies the two-way and universal use of trunk lines and compliance with attenuation standards, and also reduces the range of products linear equipment CSK. The connection with the DSL is type A in accordance with recommendations G.703 and G.812 of the CCITT. The SCT interface module with digital paths allows you to connect internal and external DSL, grouped into linear paths of 2048 or 1024 kbit/s using the AMI or HDB3 linear code.
If necessary, an economically feasible connection to the Kvant digital switching system of external analog lines is allowed. The joints with them are type C1 (for lines with PDK) and type C2 (for FSLs) in accordance with recommendations Q.517, Q.522, Q.543 and Q.544 of the CCITT. The BALK module with KSL interface with FSL contains SL (KSL) kits of different types, allowing the use of:
Three-wire SL, ZSL and SLM single-acting with a loop resistance of up to 3000 Ohms for SL and ZSL and up to 2000 Ohms for SLM, wire resistance "c" up to 700 Ohms, insulation - at least 150 kOhm and with a capacitance of up to 1.6 μF for SL and ZSL and up to 1.3 μF for SLM;
Two-wire single-acting and universal double-acting lines with a loop resistance of up to 2000 Ohms, insulation - over 50 kOhms and a capacity of up to 1 µF.
The KSL junction with lines compacted by the SP CHK allows you to organize one-way CLs, ZSL or SLM, as well as double-sided universal CLs in four-wire channels of the SP.
TEZ joint with AL (SAL) is installed, if necessary, instead of one of the TEZ AK2.
The maximum permissible number of external communication directions in the Kvant CSK is limited only by the technically possible number of connected linear paths for a specific system configuration.
Interaction of the Kvant automatic telephone exchange with oncoming automatic telephone exchanges (AMTS) of external communication directions occurs through the exchange of linear and control signals (LUS). Over external DSL, linear and ten-day address signals are transmitted in the corresponding signal channel intervals (CI) of linear paths. In these CIs, depending on the linear signal coding method used, 1...4 VSK can be assigned to each conversational LT channel. The conversion of linear signals received from the VSK into an intra-system format, their transmission to the KM control device via the intra-system signal channel (VSSC) and the reverse actions for signals from the control unit in the CSL are performed by the SCT controller of the SCT module. Any standard linear signaling codes can be programmed into the SGT.
For multi-frequency signaling, the SCT module is transparent. The exchange of dual-frequency code combinations “2 of 6” is ensured by connecting digital multi-frequency generators (GFR) and receivers (DMA), respectively, through the switching field. Any method of multi-frequency exchange is possible - pulse shuttle, pulse packet and non-interval packet.
When analog physical lines are included in the Kvant CSK, the choice of the type of lines is determined by the conductivity of the lines, the method of their use (one-way or two-way) and the method of exchanging linear control signals in the corresponding direction. Actually, CSLs ensure exchange linear signals direct current and decade code battery pulses. When turning on universal two-way FSLs, signaling with a time code with an inductive method of transmitting control signals is possible. Interaction of KSL with UU KM - according to VSSK. For multi-frequency signaling, the KSL module only performs analog-to-digital conversion dual-frequency code combinations.
For analog CLs with PDK, you can use different types of CSLs, providing standard methods for exchanging LUS via CLs, ZSLs or SLMs formed by SP channels. Depending on the type of SP PRK and the equipment system of the oncoming station, linear and ten-day address signals are transmitted over conversational channels with a frequency of 2600 Hz, through one or two VSK, or through one VSK and one signal channel in the conversation spectrum. For two-way universal trunk lines, it is possible to use a time code.
In general, the SCT and KSL modules ensure, for any type of line, the interaction of the CSK "Kvant" with all types of ten-step, coordinate, quasi-electronic and electronic stations available on communication networks, as well as with active digital switching systems of various types. Of the internationally agreed standard signaling systems, R2, R1.5 are also provided, and in 1997, signaling system No. 7 will be introduced according to general channel signaling system (SS No. 7), which will significantly expand the possibilities of interaction with any modern digital switching systems and will allow the creation of digital digital switching systems based on the PBX of the Kvant system.
2.4 Insidedancesignalingand synchronization system
Intra-system signaling in the digital switching system "Kvant" is organized by sixteenth CIs of all internal PCM paths between system modules (KM, VKM, BAL, SCT, KSL). In each CM, these VSSK are constantly connected by the UKS 32x32 block to the zero path of the PCM to the KVV9 input-output channel device, which temporarily stores, converts and transmits signal information from the control device to the VSSK and vice versa.
The synchronization system of ATS "Kvant" is constructed as follows. Each UKS is equipped with its own duplicated clock generator of the second level of the hierarchy (TG2) with quartz stabilization. The role of TG2 is performed by GR UKS. Different UCS stations are connected to each other using a switching systems synchronization unit (SCS) equipped with TG1 (HPP). Generator TG1 has increased stability, is the leader for TG2 KM and synchronizes their operation, as well as the operation of the SCT and KSL modules connected to them. If there are several TG1, one of them is appointed as the leader. It is possible to connect to TG1 and external reference TGs. TG1 generators of different stations of the Kvant system can also mutually synchronize each other.
On the remote switching module, TGs are used, synchronized from the side of the reference station by selecting clock frequencies from the group signals of the corresponding PCM paths by the SCT VKM block.
Synchronization of the operation of the remote subscriber module is achieved by separating clock frequencies from the group signals of the PCM paths from the reference station or remote switching module. (C) Information published on the site
Any TG2 or TG1, when the leading clock signals disappear, goes into independent operation mode.
2.5 Questions about power supply andplacement of equipment
The energy source for stations and remote modules of the "Kvant" system is a 380/220 V AC network, the voltage of which is converted into the main reference DC supply voltage of 60 V with permissible limits of change of 54...72 V. Loss or reduction of the reference DC voltage below 54 B causes the station to stop (VKM, VAM). After voltage appears, the equipment's functionality is automatically restored in no more than three minutes.
All constant voltages equipment supply, as well as the temporary backup power supply voltages of critical elements of the CSK (the technical operation computer and its external devices) are formed by secondary conversion of the reference voltage of 60 V. Combined BOD and BPKM units are used, providing voltages + - 5 ± 0.25 V and + - 12 ± 0.50 V. All secondary power supply units are protected against short circuits at the output and automatically restore the operating mode when the short circuit is eliminated. When directly powering equipment with a voltage of 220 V, a BP 220-60 unit is installed in the appropriate cassettes.
Support stations and remote modules of the system are also equipped with buffer or separate rechargeable batteries that provide at least three hours for OPS, TS or OPTS and six hours for VKM with a voltage of 60 V in the event of a loss of AC power. For stations with a capacity of over 4000 AL, it is recommended to provide two independent power feeders 380/220 V. The total power consumption from a 60 V source depends on the specific composition of the equipment and on average ranges from 0.6 to 1.0 W per one AL or SL in depending on the composition of the equipment.
The equipment of CSK "Kvant" is installed in cabinet-type cabinets with a width of 805 mm and a depth of 325 mm. The cabinet accommodates up to six cassettes, which, depending on the type, have from 17 to 34 places for standard replacement elements (TEZ). The dimensions of cassettes and TEZs comply with the European standard. The weight of a fully equipped cabinet does not exceed 300 kg. Up to ten cabinets are installed in one row, which are attached to the floor and to each other. The height of the row with cable height is 2800 mm (2580 mm for a row with one cabinet). Static rows are served from both sides and are placed with front or back sides facing each other at a distance of 925...1185 mm. The resulting load on the roof does not exceed 450 kg/m2.
The design of the system is highly durable and ensures that the equipment remains operational even during earthquakes of up to eight points on the Richter scale (up to ten when installed in earthquake-resistant buildings).
Go to the list of essays, coursework, tests and diplomas
discipline
Modernization of the telephone network in rural areas of the Republic of Kazakhstan
INTRODUCTION
1. Analysis of the current state of the network from Urjar, East Kazakhstan region
2. Purpose and objectives of the project
3. Statement of the problem
4. Trends in the development of STS
4.1.Development of telephone communications in rural areas
Rural communications
Rural network modernization
Modern requirements for STS modernization
Digitalization of rural communications: switching issues
Requirements for equipment parameters
5 Selecting a digital switching system
6 Main characteristics of SI-2000
6.1 Main characteristics of PBX type SI-2000
6.2 Hardware
6.3 Software
6.4 Mechanical design
6.5 Common channel signaling
6.6 Functional diagram of the SI-2000 station
7 Load calculation
7.1 Initial data
7.2 Calculation of the resulting load
7.3 Load distribution
7.4 Distribution of load intensity by direction
7.5 Calculation of the number of incoming and outgoing PCM lines
8.Calculation of equipment volume
9. Reliability calculation
9.1 Reliability indicators
9.2 Reliability calculation
9.3 Calculation of the experimental signaling link
10. Assessment of the quality of speech signal transmission over communication channels and analysis of the QS with a queue
10.1 Assessment of the quality of speech signal transmission over communication channels
10.2 Analysis of QS with accumulation
11. Life safety
11.1 Zero calculation
11.2 Artificial lighting
11.3 Automatic fire extinguishing systems
12. Business plan
12.1 Project goal
12.3 Business plan object
12.4 Services
12.5 Clients
12.6 Financial plan
Conclusion
Bibliography
1. Analysis of the current state of the network p. Urjar, East Kazakhstan region.
Telephone network of the Urjar regional telecommunications center of East Kazakhstan region.
Currently, the network of the Urjar region operates analog coordinate system equipment of the type ATSC - 100/2000, two stations, one in the village of Urjar, the other in the Makanchinsky production and ATSC - 50/200, sixteen stations that are used in the remaining communication departments of the region with the central station.
The total installed capacity of the Urjar RUT network is 6150 numbers, the used capacity is 5985 numbers.
Existing PBX networks are built using a cabinet system using direct power. Rural PBX networks are built using direct power supply.
The existing telecommunications network in the Urjar RUT is built using the “nodal method”. Long-distance communication is carried out through an automatic telephone exchange of Semipalatinsk type "C&C-08" (PRC) through K-60 compaction equipment. VKSLM-24 channels, IKZSL-30 channels are involved. Communication between the central station and Urdzhar and terminal stations are carried out using a transmission system such as “DAMA”, KNK-12, IKM-15, V-3-3S and LBK-12. With Makanchinsky production through “3” On the network of the Urdzhar regional telecommunications center, five-digit numbering of subscriber lines is adopted and two-digit numbering of special services.
Table 1.1 – Types, capacities and numbering of existing telephone exchanges
| TsS-21 | With. Urjar | ATSC-100/2000 | 2000 | 2000 | 21-000 – 22-999 |
| OS-231 | With. Besterek | ATSC-50/200 | 100 | 100 | 23-100 - 23-199 |
| OS-241 | With. Aktuma | ATSC-50/200 | 200 | 200 | 24-100 - 24-299 |
| OS-243 | With. Kyzyl-Tu | ATSC-50/200 | 50 | 40 | 24-300 - 24-349 |
| OS-245 | Novo-Andreevka village | ATSC-50/200 | 100 | 100 | 24-500 - 24-599 |
| OS-246 | With. Sholpan | ATSC-50/200M | 150 | 135 | |
| OS-251 | With. Aksakovka | ATSC-50/200M | 200 | 180 | |
| OS-253 | With. Altyn-Shoka | ATSC-50/200 | 150 | 130 | 25-300 - 25-399 25-400 - 25-449 |
| OS-255 | v.Taskesken | ATSC-50/200 | 200 | 200 | |
| OS-261 | With. Eltai | ATSC-50/200M | 150 | 150 |
26-200 – 26-299 |
| OS-263 | With. Zhanai | ATSC-50/200 | 100 | 90 | 26-300 - 26-399 |
| OS-264 | With. Karakol | ATSC-50/200M | 150 | 145 |
26-700 – 26-799 |
| OS-265 | With. Southern | ATSC-50/200 | 150 | 140 |
26-600 – 26-699 |
| OS-271 | With. Segizbay | ATSC-50/200 | 50 | 45 | 27-100 - 26-149 |
| OS273 | With. Kokozek | ATSC-50/200 | 100 | 100 | 27-300 - 27-399 |
| OS-275 | With. Eginsu | ATSC-50/200 | 100 | 80 | 27-500 - 27-599 |
| OS-281 | With. Nahuals | ATSC-50/200 | 200 | 200 |
28-100 – 28-199 28-200 – 28-299 |
| US-310 | With. Makanchi | ATSC-100/2000 | 2000 | 1950 | 31-000 – 32-999 |
| Total | 6150 | 5985 |
To improve the quality of communication and provide subscribers with new types of services, it is necessary to replace the analogue PBX with an EATS. The presence of a large population engaged mainly in livestock farming, peasant farms and private enterprises will lead to a significant increase in the number of subscribers. The expected increase in income will reduce the payback period of the network.
To more fully meet the population's needs for communication services, it will be necessary to replace the physically and morally outdated ATSK-100/2000 CS and ATSK-50/200 OS with more advanced digital switching equipment, which will create not only a modern telecommunications network, but also provide users with a wide range of range of high-quality communication services.
Modernization of STS can be carried out in two stages:
at the first stage it is necessary to replace the existing CS ATSK-100/2000 in the village of Urdzhar with a digital station;
At the second stage, it is necessary to replace the analog OS with a digital one.
This project proposes consideration of network modernization: replacing the coordinate ATSC-100/2000 in the village of Urdzhar with a digital ATS station.
Installing a digital PBX will improve the quality of operation and reliability of the network, reduce the footprint, and improve the quality of services provided.
Since it is very cumbersome to consider the replacement of all terminal PBXs together with the central one in the diploma project, it was proposed to consider only the replacement of ATSC-100/2000 with a digital PBX.
Table 1.2 – Capacity of the STS of the Urjar region.
|
|
Populated |
The type of ap-tour is compacted. |
Mounted |
Enabled |
| CA | With. Urjar | K-60P | 60 | 58 |
| 1-OS | With. Besterek | LVK-12 | 12 | 7 |
| 2-OS | With. Aktuma | IKM-15 | 15 | 10 |
| 3-OS | With. Kyzyl-Tu | V-3-3Сх2 | 6 | 5 |
| 4-OS | Novo-Andreevka village | "Lady" | 6 | 6 |
| 5-OS | With. Sholpan | IKM-15 | 15 | 9 |
| 6-OS | Aksakovka village | IKM-15 | 15 | 10 |
| 7-OS | With. Altyn-Shoka | LVK-12 | 12 | 9 |
| 8-OS | With. Tuskesken | KNK-12 | 12 | 12 |
| 9-OS | With. Eltai | IKM-15 | 15 | 9 |
| 10-OS | With. Zhanai | IKM-15 | 15 | 7 |
| 11-OS | With. Karakol | IKM-15 | 15 | 9 |
| 12-OS | With. Southern | LVK-12 | 12 | 9 |
| 13-OS | With. Segizbay | V-3-3S | 3 | 3 |
| 14-OS | With. Kokozek | IKM-15 | 15 | 7 |
| 15-OS | With. Eginsu | IKM-15 | 15 | 7 |
| 16-OS | With. Nahuals | IKM-15 | 15 | 10 |
| 17-US | With. Makanchi | KNK-12 | 24 | 24 |
| Total |
2. Purpose and objectives of the project
The goal of the project is to improve the quality of communication and the growth of income from the provision of communication services on the STS network with Urjar by replacing outdated analogue equipment with digital PBXs. Ensuring access of the rural population to modern telecommunications services and equal rights of citizens throughout the country in access to information. Eliminate the imbalance between rural and urban populations in terms of living standards, education and other social services.
With the introduction of new technologies, reduce operating costs and increase the income and economic return of the STS network with the expansion of the network. Improve the quality of communication services and ensure the creation of investment and legal conditions that will help reduce the difference in telephone density in rural areas from the average urban level, eliminating a significant gap in information support for rural residents and agricultural producers
3. Statement of the problem
Replace the existing PBX 100/2000 for 2000 numbers with an electronic PBX SI-2000 with a capacity of 4000 numbers.
To solve this problem, the following questions were worked out:
a) load calculations have been made:
calculation of the emerging load;
distribution of the resulting load;
distribution of load intensity by directions;
calculation of the number of incoming and outgoing PCM lines for the designed station.
b) Calculations for communication reliability:
communication reliability indicators;
reliability calculation;
calculation of the experimental signaling link.
c) Calculation of the reliability of the QS with accumulation and determination of the quality of the speech signal:
calculation of QS with accumulation;
calculation of the quality of the speech signal.
4 TREND IN STS DEVELOPMENT
4.1 Development of telephone communications in rural areas
Today, in rural areas, the level of telephone coverage is several times lower than in the city. This is primarily explained by the unprofitability of rural telephone communications (RTS), the main reasons for which are: the remoteness of some subscribers from the telephone exchange, as a result of which the costs of its operation and development are three and seven times higher than average annual income; small number of subscriber groups; the difficulty of forecasting capacity growth in populated areas, as well as other factors that do not contribute to the interest of telecom operators in the development of STS.
At the same time, the analysis shows that the cost of telephone installation in rural areas pays off two to three times faster than in cities, and if all social and economic factors in generating income by telecom operators, users of communications equipment and society as a whole (region, state) are considered in taken together, it becomes obvious that the profitability of STS is achieved already at a density of 14-16 telephone sets (TS) per 100 people. One cannot discount the fact that the presence of a developed rural communication infrastructure greatly contributes to increasing the efficiency of agricultural production.
In 1965-1991 The development of telephone communications in Kazakhstan was carried out in accordance with government regulations. At the initial stage, more than 50 percent of the introduced capacity of the STS was intended for the production needs of agricultural enterprises (Agricultural Enterprises). The STS had the status of intra-industrial telephone communication (IPTS) and was financed from budgetary allocations for the Agriculture sector, as well as from collective farms. At the same time, the volume of telephone installations was constantly increasing. So, if in 1966-1970. 320 thousand numbers were introduced, then in 1985-1990. - more than one million
However, the subsequent cessation of the allocation of funds for rural telephone installation from the budget, the weakening of the economic potential of rural commodity producers, the lack of money from the population, the uncertainty of the government’s economic strategy in lending to the development of STS led to a sharp decrease in the provision of agricultural enterprises with the necessary means of communication and the cessation of the introduction of modern information technologies and various communication services. As a result, now a significant number of farms, garages, workshops, grain warehouses and other important production facilities do not have electrical communications.
Based on the fact that the availability of the necessary means of telephone communication of agricultural enterprises is the most important condition for increasing the livelihoods of the rural population and the growth of agricultural production, and that the absence of these means will not allow overcoming the crisis in the agro-industrial complex (AIC), the government, the Ministry of Agriculture and the Ministry of Communications together with governments and administrations subjects of the Republic of Kazakhstan, as well as with other interested ministries and departments, it is necessary to immediately resolve issues related to accelerating the development of STS in the coming years. As a first step, a program for the development of telephone communications in rural areas should be adopted, which will create a flexible and cost-effective information structure in the agro-industrial complex, covering all levels of production and processing of agricultural products and providing management structures and the population with new information services.
One of the main tasks of regional communications enterprises and agricultural enterprises should be to develop a mechanism for investing in the development of telecommunication networks, and the consequence of its implementation is a consistent increase in the profitability of the telephone network and the region as a whole due to an increase in the number and types of communication and information services, which are paid off by increasing agricultural production. In this regard, it is necessary to solve three main problems:
economic
technical
organizational
The economic task of regional telecom operators is to develop appropriate management functions to determine user needs for information services for the next five to seven years and their implementation in accordance with the prevailing economic conditions. There is a need to focus them on developing a business plan that is balanced in terms of income and expenses, as well as obtaining the planned income and investment attractiveness of the created STS. The solution of economic problems when installing rural telephones should be carried out by the JSC
Kazakhtelecom works in close contact with the relevant financial services of governments and administrations of the constituent entities of the Republic of Kazakhstan, agricultural authorities and heads of regional administrations in accordance with the annual budget allocation plan approved by state assemblies or regional regions.
On the agenda of all regional and district administrations and agricultural authorities should be the issue of a mechanism for allocating budgetary and extra-budgetary funds for shared participation in the construction of STS as the basis for the social development of the village and the rise of the agro-industrial complex.
Technical tasks.
When solving the economic problem of installing telephones in rural areas, special attention should be paid to the imperfection of certain technical solutions for organizing communications, which complicate the provision of communication services to rural producers and the population.
As an analysis of STS modernization has shown, in a number of regions there is not even a network development plan (expansion of the service area, service requirements, methods of distributing subscribers, expected growth of schedules, etc.) for the next five to seven years. And the technical factor plays a dominant role in improving the economic indicators of the development and operation of STS. Underestimation or misunderstanding of the importance of developing technology for network development for the future and its feasibility study does not allow for economical telephony in rural areas. The use of traditional telephony technologies with a central - hub - terminal PBX structure (even when using digital PBXs) cannot ensure break-even operation of communication networks at telephone density.
In developed countries, radio access is widely used in rural areas when it is necessary to install new telephones or provide subscribers with new communication services in the absence of subscriber lines or the impossibility of increasing network capacity. The choice of radio access technologies and standards is one of the most important issues when organizing radiotelephone communications in rural areas and especially in areas with low population density.
There are many radio access systems that differ in purpose, methods of interaction with the core PBX, frequency spectrum, types of modulation, initial and final capacity, etc. The quantity and quality of the services provided, and therefore the cost of entering the number, depend on these system parameters.
4.2 Communications in rural areas
Effective telecommunication is an important aspect for the economic well-being of rural areas. Regions with low population density occupy a significant part of the territory of Kazakhstan.
Economic development and efficiency of rural communications requires detailed planning involving appropriate equipment, technology and economic methods, starting with the construction of an exchange based on the existing telephone network and the creation of a rural network construction plan that is flexible enough to meet changes in capacity needs, types service, location and advances in technology when they become available.
There are several ways to develop communications in rural areas:
Introduction of digital switching equipment and standard digital transmission systems;
Use of radiotelephone, space communications and radio relay lines in hard-to-reach and sparsely populated areas, where telephone installation by traditional methods is difficult and economically ineffective.
4.3 Rural network modernization
Modernization of existing rural automatic telephone exchanges (ATS) is carried out in order to improve the quality of communication with minimal capital investments and is mainly reduced to replacing equipment with the least degree of possibility. In addition, analogue transmission systems are being replaced with digital ones, as a result of which inter-station exchange is carried out via PCM-30 or PCM-15 channels; automatic connection cost accounting (ACCA) of SATS diagnostic equipment is being introduced; automatic number identification (ANI) is being introduced or replaced. However, the modernization of existing SATS does not solve such important problems as increasing number capacity and introducing new types of traditional services (local and long-distance communications, emergency order and information help services of Far Eastern Branches, ISDN services) and those generated by new technologies (data transmission, Internet access).
To solve these problems, it is necessary to introduce a new generation of digital PBXs on STS, as well as to build a subscriber access network and high-speed primary networks.
Let's consider the main stages of digitalization of STS.
First stage
In the early 90s of the last century, the introduction of SATS began on telephone networks in Kazakhstan. Due to the fact that a digital PBX must ensure interaction with all types of telephone exchanges existing on STS, as well as in rural areas, departmental and commercial networks.
A mandatory requirement for digital SATS is the implementation of the Caller ID function using multi-frequency code signaling using the “non-interval packet” method to ensure automatic long-distance communication and calling local telephone network services without dialing your own number.
The Caller ID request can arrive at various stages of the connection from the incoming side of the telephone exchange, the USS, the functions of which can be performed by a CA, or from the local network's PBX. In addition to the caller ID function, special physical services for servicing calls on the PSTN include the need for priority, the need to ensure the priority of long-distance calls received over long-distance (LLD) over local ones. To do this, the SATS must provide:
connecting a long-distance telephone operator to a busy subscriber recently (it is planned to replace it with an algorithm similar to the service (Call Waiting);
the possibility of the called subscriber refusing a local connection in favor of a long-distance connection;
processing a repeat call from a long-distance operator.
Release of a connection established via SLM only from the side of the long-distance exchange. Despite the availability of OTT for all types of SATS, the requirements for central stations (CS) of the STS and for rural-suburban communication nodes (USC) differ significantly from the requirements for terminal stations (OS) and hubs (CN). CS, USP installed in the regional center are built on the basis of powerful switching platforms from well-known manufacturers and are characterized by a complex architecture of hardware and software (software), which provide:
high reliability of equipment (redundancy of main units);
significant capacity.
The capacity of the serviced load and the performance of the control devices of the CS, USP must be sufficient to serve subscribers of the entire STS. Currently, STS is being built within one administrative district. However, during the transition to a promising network, it is assumed that one STS and several administrative districts will be served.
In this regard, installing a central telephone network or USP of insufficient capacity may not be a promising solution, which will not allow expanding the existing telephone network without significant additional costs and combining local telephone networks of various rural administrative districts into one larger one, which will also include the process of digitalization and the introduction of promising technologies.
Reliability requirements for the CA and USP should be higher than for the GATS, since the failure of the CA and USP will lead to STS subscribers losing the ability to establish both external connections and a significant part of the connections within the STS itself.
PBXs used as CS and USP are additionally required to interact with automatic telephone exchanges via the NL and SLM intrazonal network and with information, reference, and emergency services of the rural administrative region.
This may require the presence of additional interfaces and signaling protocols (linear at a frequency of 2600 Hz via digital or physical four-wire ZSL, SLM; linear via three-wire physical connecting lines, registered multi-frequency code using the “pulse packet” method). Implementation of interfaces with the CTE is required. , ASR. It is possible to combine the functions of the CA (possibly USP) and USS.
Due to the fact that the STS still requires semi-automatic communication, the CA must provide the ability to interact with the MTS of the regional center. It is advisable to replace the existing MTS with electronic equipment for telephone operator workstations, which is part of the CA or supplied separately, connecting to the CA via a PCM path.
Other requirements apply to the control system and OS installed in any locality. First of all, this is the low cost of the equipment and the ability to operate in an unattended mode (remote maintenance and operation).
In addition to SATS, operational dispatch communication systems and UPBX are used in rural areas. Today, most of the existing analog communication consoles are obsolete and physically worn out.
Modern digital stations have taken on part of the operational communications load. Operational dispatch communication systems have various modifications: from simple systems like “Director-Secretary” to complex systems characterized by flexibility and a large number of additional functions.
Let's consider various strategies for digitalization of rural networks, and their advantages and disadvantages.
Digitalization strategies while maintaining the old CA
In real digitalization projects, STS is often carried out “from below” and involves, first of all, replacing the OS or USP with digital ones, while the telecom operator is satisfied with the existing station as a CA or USP for a number of reasons:
The central station is located in a large populated area and the problems of its maintenance and operation are easier to solve than for stations located in small populated areas;
due to the increased reliability of the CA/USP quality, operators want to see products from well-known domestic or foreign manufacturers;
Replacing the CA/USP will require significant capital investment.
4.4 Modern requirements for modernization of STS
The modernized rural network assumes: the use of digital telephone exchanges of greater capacity than currently available in combination with unattended subscriber extensions.
Modern networks are built using remote hubs connected to base or main exchanges using radio relay, fiber and satellite trunks. On modern communication networks, the digital flow of information must be delivered directly to the subscriber.
Modernization of rural communications involves, in addition to replacing switching equipment, modernizing the primary network using both wired and wireless transmission systems (radio relay), providing the ability to organize standard PCM paths with a transmission speed of 2048 kbit/s;
If there is a lack of financial resources, the option of temporary incomplete modernization should be provided.
An option for incomplete modernization is the simultaneous operation of two digital systems: the old one to be dismantled and the newly introduced digital one, as well as the replacement of used and most unreliable units with electronic analogues. For example, replacing RA with an electronic register RE for ATSC 100/2000. Replacing ISHK relay sets with electronic ones to prevent the telephone number from being distorted by the telephone exchange (caller ID substitution). Such cases have occurred, unscrupulous subscribers distorted their number and it was not possible to present an invoice for the negotiations. However, for worn-out telephone exchanges, as well as for those where it is desirable to achieve a sharp increase in communication quality, radical modernization is desirable. The fact is that electronic analogues of relay devices are forced to have significant redundancy associated with the coupling of the internal signal levels of electronic units with the levels of relay devices. Let's add a power supply and a housing for each device and see that all this leads to a noticeable increase in the cost of a complete block re-equipment of a telephone exchange compared to a complete modernization. Unfortunately, no one has yet brought this option to industrial production.
Structure requirements:
The structure of the telephone network, if possible, should ensure the transition from a radial-node to a radial (single-level) structure of the telephone network with the inclusion of OS and subscriber access equipment mainly in the central network with the organization of new and expansion of existing cross-links between the OS. A single-stage scheme for constructing a communication network (without a control system) increases reliability and reduces connection establishment time and, therefore, is more promising. The two-stage construction is maintained subject to the technical and economic feasibility of node formation. To increase the reliability of communication in the STS, a ring structure of the primary network can be used. Due to the large territory covered by one rural telephone network, direct connection of all subscriber lines to one or several stations located in the regional center is not economically justified. Therefore, STS uses zoning and node formation with varying degrees of decentralization of station equipment (distributed structure).
The requirements for the structure of the STS, discussed above, remain the same when modernizing rural networks, which is mainly due to the high costs of creating and operating a digital primary network and the low attraction between stations installed in different settlements of the rural area. In real networks, the structures considered are usually combined depending on specific conditions: the location of stations in the area, its area, and the capacity of stations.
Requirements for rural switching stations:
The requirements for switching equipment used to modernize rural areas are largely determined not only by geographical features and the historical structure of rural telephone networks (RTN), but also by the adopted call servicing algorithms to ensure the priority of long-distance connections over local ones and the transmission of caller ID information. Due to increased requirements for network reliability, operators want to see products from well-known foreign manufacturers as CAs.
While maintaining the existing transmission systems and inter-exchange signaling, the newly introduced CA must support the interfaces and protocols existing on the network.
The rural switching station must meet all requirements (for capacity, taking into account development prospects, a set of signaling protocols) and have a certificate of conformity allowing its use as a CA.
Requirements for subscriber access networks
For the existing telecommunication system, the subscriber access network is a collection of AL. The State Committee for Communications put into effect on January 1, 1998, industry standard 45.83-96 “Rural telephone network, subscriber lines, operating standards.” The standard establishes standards for electrical parameters on direct and alternating currents of AL circuits and their elements that ensure operation.
Telephone systems:
telegraph communication systems, including public telegraph services, subscriber telegraph, telex;
telepathic services, including fax, video text, e-mail, message processing services;
data transmission systems;
sound broadcasting program distribution systems;
digital systems with service integration.
The normalization of the electrical parameters of AL circuits in the standard is given taking into account their aging during their service life.
The requirements of this standard must be taken into account when operating, designing, constructing new and reconstructing existing lines of rural telephone networks.
The structure of AL STS construction provides for:
backbone section (from the exchange terminal to the distribution cabinet);
distribution section (from the distribution cabinet to the distribution box);
subscriber wiring (from the junction box or cable box to the telephone socket).
Direct connection lines from the PBX cross-country to the subscriber are also used. AL STS uses subscriber high-frequency installations with frequency division of channels. subscriber digital concentrators and multiplexers.
For AL STS use:
cables of the TPP type with copper conductors with a diameter of 0.32, 0.4 and 0.5 mm with polyethylene insulation and in a polyethylene sheath;
cables type TG with copper conductors with a diameter of 0.4 and 0.5 mm with paper insulation and lead sheath;
few pair cables type KTPZShp with copper conductors with a diameter of 0.64 mm with polyethylene insulation, hydrophobic filling of the core and in a polyethylene sheath
single-pair cables of the PRPPM type with copper conductors with a diameter of 0.9 and 1.2 mm with polyethylene insulation;
steel chains of overhead and mixed communication lines.
Subscriber wiring is carried out using single-pair wires such as TRP and TRV. Connections in cross-connections and distribution cabinets are made using PKSV cross-connecting wires with a copper core diameter of 0.4 and 0.5 mm. For groups of remote subscribers, the use of analogue concentrators is provided. In the section from the automatic telephone exchange to the analog concentrators, cables such as TPP, KTPZShp, KSPZP, overhead and mixed communication lines are used.
In the section from the hub to the subscriber, PRPPM, TPR cables, aerial and mixed communication lines are used.
Basic requirements for subscriber radio access systems for rural areas:
organization of high-quality and stable communications in large areas with low population density (from 1 to 5 people/km2) in networks serving from 30 to 240 subscribers;
removal of base stations (BS) via cable communication channels at a distance of up to 20 km;
organization of small local mobility zones in regional centers;
removal of user equipment to a distance of up to 10 km from the BS;
the ability to remotely manage and monitor access equipment from a regional center;
possibility of modular expansion of systems;
ensuring data transmission at a speed of 32 kbit/s for organizing Internet access and using telemedicine applications;
low cost of equipment with low operating costs.
To ensure stable and high-quality transmission of small volumes of traffic in large areas with low population density, you can use a system design that combines a BS controller that generates one E1 stream directed to the core PBX (signaling type EDSS1 or V5.2), small-channel BS (4- 6 channels) and radio repeaters. Relocation of base stations via cable communication channels over a distance of up to 20 km is carried out using MDSL or G.SHDSL technology. When building communication systems in linearly extended populated areas, it is necessary to provide in the BS the possibility of multiplexing channels.
4.5 Digitalization of rural communications: switching issues
The requirements for switching equipment used for telephony in rural areas are largely determined not only by geographical features and the historically established structure of domestic rural telephone networks (RTN), but also by the adopted call servicing algorithms to ensure the priority of long-distance connections over local ones and the transmission of Caller ID information. It is from these purely pragmatic positions that the authors of the article tried to consider the problems of switching systems for real STS.
Traditional construction of STS
Historically, in Kazakhstan, the STS was created within a rural administrative district. Due to the low population density in rural areas, the construction of STS required a significant number of low-capacity switching systems to concentrate the telephone load in places where subscribers accumulate (populated areas).
The radial (single-stage construction) or radial-nodal (one-, two-stage construction) structures with the possibility of organizing cross-links, adopted for the construction of the STS, assume the presence of the following types of stations, differing in the way they are connected and the functions they perform:
central station (CS), installed in the district center and simultaneously performing the functions of the telephone exchange of the district center and the transit node of the STS;
a junction station (US), used only for radial-node network construction and installed in any populated areas of a rural area;
terminal station (OS), installed in any settlements of the rural area.
Rural stations also include rural-suburban communication nodes (U SP), intended for organizing transit communications on combined (rural-suburban) local telephone networks.
Table 4.5 - Interstation SATS interfaces
USP is used in cases where the capacity of the telephone network of the regional center is large enough and cannot be serviced by one CA. In this case, a regional telephone network is organized in the regional center, and USP is included in it as a transit node.
USP establishes communication both between STS stations and with stations of the city telephone network (GTS). Through USP
Calculation of an acceptable collision domain configuration for a local network. Design of horizontal and vertical lines, main wiring. Development of a cable system plan for connecting all computers to the network. Selecting the location of equipment rooms.
Design and Development Perspectives static converters average power. Calculation of currents and voltages. Selection of thyristors and coolers. Calculation of smoothing filter and choke. Selection of capacitors. Electromagnetic calculation of a transformer.
Selecting the type and lighting system. Selecting a lighting device and placement. Determination of the power of the lighting installation. Electrical equipment maintenance area. Selecting the power supply circuit and supply voltage for the lighting installation.
Recommendations for installing fire alarm control devices: the premises must be equipped with security and fire alarm and is protected from unauthorized access. Layout of equipment in the room. Communications of warning systems.
Calculation of the main dimensions of the auditorium of a wide-screen cinema with a capacity of 720 seats, intended for demonstrating wide-screen, regular, and cassette films. Stages of planning visual seats, selection of sound-reproducing equipment.
Methods for creating a transmitting device for a radio altimeter transceiver module. Feasibility study of the work. Ensuring the safety of personnel working on the project. Classification of production by fire and explosion hazard.
Calculation of static characteristics of the electric drive of the generator-motor system. Determination of dynamic parameters and boost coefficient. Calculation of resistors in the generator excitation winding circuit. Determination of the resistance of resistors R1, R2, R3 and R4.
Study electrical circuit AC at serial connection active, inductive capacitance. Changing the active resistance of the inductor. Parameters of the electrical circuit of single-phase alternating current.
Determination of the expected total design load. Determination of the number and power of GPP transformers, external power supply circuits. Determination of voltages, voltage deviations. Calculation of short circuit currents. Operating costs.
Methodology for calculating a low-power air-cooled transformer. Selecting a magnetic core, determining the number of turns in windings, electrical and structural calculations. Determination of losses, magnetizing current in steel; calculation of voltage drop and efficiency.
Current and voltage converters, their properties and applications. The concept of transformation ratio, reactors and transreactors. Phase-shifting and frequency-dependent circuits. Saturable current transformers, sinusoidal current and voltage converters.
Reconstruction project for ATS-62/69 in Almaty with the replacement of ATSSH with a digital ATS
graduate work
1.3 Principles and requirements for modernization of the public telephone network
Concept for the development of the telecommunications services market. First of all, a pragmatic approach to PSTN modernization is proposed, based on the development of the network towards the provision of new telecommunication services.
Existing approaches to PSTN modernization. Issues of PSTN modernization arose earlier and were mainly related to the fact that the service life of switching systems (SC) is 40 years. Naturally, during operation, technical problems arose that needed to be solved. However, all decisions, including digitalization of equipment, were carried out as part of the provision of basic services ( phone call) and the unconditional predominance of voice traffic.
Today, the task of modernization has fundamentally changed. Its main goal was network packetization. The term “softswitch” can be used to describe a fairly wide range of communications solutions for next generation networks (NGN). The translation of this term into Russian (“soft switch”), however, the phrase softswitch is used in the name commercial products a number of companies, so its use as a general term does not make their competitors very happy. The term “softswitch” in its broad sense is used to describe new generation communication systems based on open standards and allowing the construction of multiservice networks with dedicated service “intelligence”. Such networks provide efficient transmission of voice, video and data and have great potential for deployment additional services than traditional PSTN. Convergence from circuit-switched networks to packet/frame/cell switched networks, the operation of which is controlled by soft-switch class systems, is actually a continuation of the protracted transition to open infocommunication environments, at one time initiated by the emergence of the concept of smart networks.
If we compare the Softswith system with traditional PBXs, the advantages are obvious; the architecture is modular, which allows easy integration for third-party applications; reconfiguration to meet customer needs; traffic can be very diverse (speech, data, video, fax); the duration of one connection is unlimited.
The most complex and important part of modern telephone switches is program code, which controls call processing procedures. He is “responsible” for making decisions on basic call routing and ensures the provision of tens and even hundreds additional services. In traditional PBX systems, the software runs on legacy hardware platforms and is tightly integrated with circuit switching equipment. It is this closed, circuit-switching-oriented architecture that explains the inability of today's PBXs to directly process traffic. packet telephony, and this in turn is perhaps the main obstacle to the much-touted convergence.
At the same time, almost all of us have already believed that the future lies in packet transmission of all types of schedules, including telephone ones. Therefore, we expect many years of transition, when we will have to deal with hybrid networks that switch both packets and channels. For this period, hybrid packet-channel switches with built-in call processing software are offered.
But such solutions are unlikely to reduce costs and increase the variety of services. Most likely, the telecommunications industry will take a different path - along the path of separating the means of call processing from the means of physical switching of the schedule using a standard protocol for their interaction. According to the terminology of softswitch systems, physical switching functions are performed by media gateways (Media Gateway - MG), and call processing logic is assigned to the controllers of these gateways (Media Gateway Controller - MGC).
What does this “separation of powers” provide? First, it opens the door to small firms that will bring a new spirit to the industry, second, it will be possible to use general software call processing intelligence for different types of networks (traditional, packet, hybrid) with different voice packet formats and a variety of physical transport. Thirdly, it will be possible to use standard computer platforms, operating systems and development environments, which will provide significant savings at all stages of the development and implementation of new services. These reasons alone are enough to jump on the softswitch idea.
The telecommunication system is divided into gateways and their controllers. For effective interaction The protocol is MGCP/MEGACO/H.248. The MGCP protocol, which is being developed by the Media Gateway Control (Megaco) group of the IETF, indicates its enormous importance in the world of telecommunications.
All the call processing intelligence is in the controller, and the gateways serve only as cross-connectors. To connect certain media streams, the gateway is guided by commands coming from the MGC. If it is necessary to provide a connection (in MGCP terminology, place in one context) different types of media streams - say, on one side an E1 stream enters the gateway, and on the other, IP voice packets exit - the gateway performs signal transcoding and other necessary operations.
To control the operation of media gateways, MGCs obviously must receive and process signaling information from both packet networks and traditional circuit-switched telephone networks.
In the case of classic telephone alarms, the situation is more complicated. Recall that this signaling - whether it is common channel (SS7, PRI ISDN) or dedicated signaling channels (CAS) - is typically carried in a circuit-switched environment, and most MGC controllers do not have direct access to this environment. Media gateway controllers are designed to be devices that connect to packet networks, so to deliver classic telephone signaling it must be packaged in a packet-based (IP) transport. The IETF SIGTRAN group, which has already proposed the SCTP (Simple Control Transmission Protocol) in RFC 2960, is focused on developing appropriate algorithms.
So, since classic telephone signaling is usually carried over a circuit-switched network, and only media gateways (and not controllers) have interfaces with such a network, it is logical to additionally implement the functions of a signaling gateway on such gateways. The latter will terminate the SS7 and PRI protocols, encapsulate their high-level messages for transmission over the IP network and deliver to the MGC controllers. And the controller will deal with the essence of the alarm system messages. Modernization requires certain requirements for switching nodes, the transport environment, and the access network
1.3.1 Access network
Information circulating in modern telecommunication networks can have different shapes(speech, data, video), and for user visibility, switching systems can use a variety of access media, including copper cable and fiber optic cable.
This is exactly how the technological base of the subscriber access network is currently changing - from copper wires to wireless and optical means. The needs of subscribers are also changing: their interest in new telecommunications services is growing. In the almost century-long history of the gradual evolutionary development of the subscriber access network, satisfied with the 3.4 kHz band and based on copper wire, the time has come for revolutionary transformations associated with the emergence of new technologies, concepts and access methods.
It was these revolutionary transformations that gave rise to an associative chain of three sources and three components access network services requested by the user. The three sources of access network services are:
speech transmission (telephone communication);
data transfer;
transmission of video information.
To provide services of each type, today there is its own subscriber access equipment, and its own communication means are used: a pair of copper wires for subscribers with analog lines and terminals, fiber-optic communication means, wireless access equipment. Thus, the access network can be divided into three components:
metal cable (twisted pair, coaxial cable and etc.);
fiber optic cable;
wireless subscriber access (WLL).
From the point of view of intensive implementation of modern means and technologies for subscriber access, a significant factor is the reduction in the total number of automatic telephone exchanges and the enlargement of switching nodes, in connection with which the user service areas and the range of access network equipment are increasing.
Another important factor is the use of the V5 open interface to connect access equipment. Supports wired and wireless (DECT standard) subscriber access, ISDN and SHDSL digital subscriber lines, which allows you to connect to switching nodes via PCM paths with a V5.2 interface.
1.3.2 Switching nodes
Switching nodes are focused on providing the ability to integrate into packet networks by equipping telephone nodes and stations with interface modules that support packet interfaces with the IP protocol, while maintaining all the interfaces of modern PSTN:
V5 interface for interaction with wired and wireless access equipment;
digital subscriber signaling system (DSS1) for connecting private telephone exchanges;
QSIG signaling for direct interaction with corporate networks;
protocol stack. OKS-7_(including IMAP for communication with the SCP of the intelligent network, which will be discussed below when considering the third article);
protocol X.25 SORM functions;
as well as an IPU (ISP PoP Unit) interface for interaction with IP networks.
The advantages of this approach to switching nodes and stations, which makes it possible to use already installed switching equipment and integrate it into packet networks, are obvious.
Design pragmatics show that this method is best suited for PSTN operators to build a bridge between traditional telephony and multiservice networks.
1.3.3 Intelligent services
Naturally, the process of convergence of each type of network brought its own technologies, conceptual solutions, and, ultimately, its own philosophy. Thus, the public telephone network in the 80s of the last century was enriched with the concept of an intelligent network, which involved removing intelligence from switching nodes and stations and concentrating it directly at the center of the network, in the so-called Service Control Point (SCP) - network control nodes services.
In smart networks, the idea of separating the service plane, representing these services as they are visible to the user and without any connection with the implementation of these services, from the global functional plane, the distributed functional plane and, finally, from the physical implementation plane will long survive itself network or protocol options for implementing IS. Network intelligence is still at the center of the network, in SCP, but there is also an HLR for mobile communications, and a proxy server for services for IP network users. All this together represents a modern interpretation of the Intelligent Network architecture, to which previously built Intelligent Networks are evolving. Still at the center of the network is the network SCP, which all three networks (fixed, mobile and IP) can access as centralized network intelligence for service logic and routing data.
As the process of convergence progressed, IP computer networks brought with them another, directly opposite trend - the trend of distributed intelligence located at the edges of the network. The origins of this approach lay in local computer networks last century and, in fact, the entire Internet is built on this principle. Therefore, this second trend is also reflected in the recommendations of the International Telecommunication Union (ITU) under the name Service Node (SN). It is also discussed in large number publications and implemented, in particular, in the domestic PROTEI platform, which also has an implementation option for SSP/SCP with INAP.
More precisely, it implements fundamentally new approach balanced use of these two principles - centralized and distributed intelligence, on the proportional use of ideas and methods coming from smart PSTN networks and from computer IP networks. This approach to the proportional architecture of the Intelligent Network is called the PRIN approach (PRIN - PRoportion Intelligent Network). Sometimes this abbreviation stands for Parlay-oriented approach or Proteus-oriented approach to building an Intelligent Network, which is also true.
The essence of this PRIN approach is that a number of services, say, federal class, are implemented using a centralized SCP connected via the INAP protocol, and some regional class services pass through one of the many SN service nodes, also recommended by the ITU, distributed on the outskirts network and enabled via PRI, ISUP and even 2VSK interfaces.
It should be emphasized that it is not necessary that federal services be organized exclusively through SCP. Today, extremely interesting technologies of distributed network intelligence have been invented that make it possible to install service logic anywhere in the network, and to concentrate routing data in network databases remote from the service logic and, thus, organize federal services based on a combination of distributed SNs.
“Call Center and Computer Telephony”, describing the Service Node approach, and “IP Telephony”, considering the services of IP-Proteus, this third component of the process of convergence of services, infocommunications, which certainly could not but influence the nature and methods of providing services. The resulting vector of these three technologies is the very optimal strategy, which is the vector sum of three vectors.
I would like to especially draw attention to the concept of a call center. The ideology of the smart network, which appeared in the 80s of the last century, did not include manual call servicing at all. This is understandable if we recall that period of idealization computer capabilities, debates about whether a computer will be smarter than a person, etc. However, over the ensuing years, Call Centers have developed extremely efficiently and have recently transformed into Contact Centers.
Modernization of the telephone network in rural areas of the Republic of Kazakhstan
The modernized rural network assumes: the use of digital telephone exchanges of greater capacity than currently available in combination with unattended subscriber extensions. Modern networks are built using remote hubs...
In the building of the main building of ASU, a TOS-120 digital telephone exchange for 180 subscribers was installed (Fig. 2.2.) with city numbering uniting three buildings (main building, dormitory No. 1 and dormitory No. 3), to date 106 subscribers are connected. (Table 2.1.) Fig. 2.2...
Construction of a GTS based on SDH
telephone network sdh cable Development of an interstation communication scheme and numbering of subscriber lines (AL)...
Construction of a GTS based on SDH
To build GTS networks, the following methods are used: a) each with each - a fully connected network, used in the case of large gravity between stations, small network size, high load intensity between stations...
A transport network at any level of the hierarchy can be represented by a set of links (two-way information exchange paths) that connect network nodes (NS) to each other...
Construction of multiservice networks
Strictly speaking, the Operator currently operates several switched networks. Among them, the telephone network dominates...
GTS project based on synchronous digital hierarchy (SDH) transmission systems
Reconstruction project for ATS-62/69 in Almaty with the replacement of ATSSH with a digital ATS
Existing public telephone networks (PSTN) were designed to serve voice traffic, i.e. to provide traditional PSTN telephone services. Telegraph messages were transmitted through a separate...
Project for the reorganization of the telephone network of the city of Gomel by replacing morally and physically outdated stations such as "Pentakonta 1000C"
Existing public telephone networks (PSTN) were designed to serve voice traffic, i.e. to provide traditional PSTN telephone services. Telegraph messages were transmitted through a separate...
Design of linear structures of a city telephone network
Determining the capacity of the district's telephone network using the formula: (1.1) Where N is the number of residents in the designed area, people. nq - number of blocks in the design area = 3067 thousand people...
Call center design
Rice. 4 Scenario for establishing an incoming connection After receiving the number digits in the Setup message, the gateway sends an INVITE request towards the operator’s equipment. The called party accepts the INVITE request and begins processing it...
Development of a data transmission network for the Nura RUT of the Karaganda region based on the creation of digital RRL
The scheme of the current communication organization is built on the radial principle of constructing rural telephone networks, the diagram of which is shown in Figure 1.1. Picture 1...
Calculation of telephone network characteristics
Solving design problems for hydraulic structures based on SP SDH
Based on the method of organizing the connecting path between end user devices, communication networks are divided into switched and non-switched...
Construction of a telephone sewer system on a low-capacity gas transmission system
Telephone cable drainage consists of underground pipelines and wells of various types, constructed throughout the city from cable shafts of automatic telephone exchanges to cable entries into buildings, into distribution cabinets and onto the supports of overhead communication lines...
The full life of any modern organization is impossible without high-quality communication - this is one of the conditions for successful business management. Therefore, sooner or later, any company faces the issue of upgrading an office PBX. The reasons for this are quite significant. The technologies used to operate a regular office PBX become obsolete over time and can no longer meet the new business challenges that the company faces. Modern technologies make it possible to bring all internal and external communications of a company into a single point: providing local communications, automatic distribution of incoming calls, voice mail, auto attendant, conference calls, recognition of fax messages - these are just a few of the benefits that a company can receive after upgrading a regular private PBX (PBX). How to choose a modernization strategy telephone system and a suitable solution? What problems might you encounter when running such a project? Natalya Dyakonova, director of the telecommunications department at CROC, answers our readers’ questions.
What questions are most important when choosing a telephone system modernization strategy? To what extent is a survey of an enterprise's IT infrastructure necessary?
Often, the reason for modernizing the telephone infrastructure is the replacement of outdated equipment that is ineffective in solving certain problems of the company. Therefore, before we begin modernization in the customer’s local or distributed network, we study the entire IT infrastructure of the company. And then we advise: “This can be improved, but here you will have to change it completely. If you want to have a modern system, you need to do everything properly.” You cannot change one element and leave another at the Stone Age level. Especially now, when most manufacturers supply convergent solutions (stations with IP streams), with the help of which long-distance and international communications can be made much cheaper.
When choosing a telephone system, it is very important to work out the issues of connecting to an operator. Our projects rarely feature stand-alone buildings; in most cases we implement distributed systems. The central station is usually installed at the head office, and they are already connected to it additional offices(branches), possibly with their own stations, which can be combined via IP streams and ISDN, using any telephone signaling. And it is very important that all these elements are integrated into a single system.
In terms of functionality, first of all, companies want the system to provide basic basic functions: call forwarding, connecting groups of subscribers, distribution into groups, voice boxes, etc. Now almost all PBX manufacturers come with this functionality bundled with equipment, but an old station, especially one purchased twenty years ago, may not have it. In addition, basic call center functionality is now often requested.
Exotic functions, in addition to the usual call center, are rarely needed, for example, when it is necessary to implement some special functions and integration with applications is required. For this you need special setting or updating the software, and this is no longer the task of the manufacturer, but of the integrator. However, each project is unique; each customer has its own applications, business processes and requirements for the integration of call centers. Almost no two solutions are alike. The equipment and software can be supplied the same, but the software settings will be different everywhere, depending on the requirements of a particular customer.
Is there a universal call center software that can work with any hardware? How popular is a solution such as a softphone now?
A call center is almost always software, but it can be installed on a station or server. Eat software products, which are installed on the server and work with almost any modern PBX. For example, the Avaya Interaction Center product is installed on a separate server and works with any station. It doesn’t matter where the voice streams come to him from, he processes incoming calls in accordance with a given logic, integrating with applications.
As for softphones, their use is more active in the IT departments of enterprises, where employees are more fluent in using computers and do not experience the moral inconvenience of switching from a regular handset phone to a headset with a microphone and headphones connected to the computer. In addition, this is a fairly popular solution among call center operators, who anyway use headsets and, in principle, do not need a regular phone. This saves time (you don’t have to pick up the phone), both hands are free, you don’t have to buy a device, it doesn’t take up extra space on your desk, and the softphone is as reliable as a regular phone. However, in general, our customers do not have many softphones, perhaps because any innovations enter our lives gradually.
Let's get back to choosing a solution. For what reasons do businesses often choose equipment from the same manufacturer as their old PBX?
The reason lies in the equipment itself, and in the customer’s availability of already trained specialists in equipment from a particular vendor, and in established relationships with the supplier.
If we talk about the technical side of the issue, many manufacturers, for example NEC or Alcatel, implement proprietary protocols and signaling. We work more with Avaya stations partly because Avaya does not use proprietary protocols and its products integrate well with solutions from other vendors. The fact is that if a company has equipment from one company, in case of difficulties you can always contact the manufacturer. But if two stations from different manufacturers are combined and some complex problem arises, it can be difficult to understand where its roots are: manufacturers often refer to each other, and a lot depends on the integrator. One of our customers has both Cisco IP telephony and NEC, Siemens and Avaya stations working together in a single system. Yes, we spent a lot of time integrating this solution, but nevertheless we were able to combine everything. In general, the most popular solutions among our customers are Avaya and IP telephony from Cisco. Nortel technology also has many admirers.
In addition, the choice of solution is influenced by the fact that most manufacturers have special migration programs from old equipment to new ones. For example, when replacing an old station with a new one from the same manufacturer, you can get significant discounts. Moreover, for example, with Cisco, old devices must be returned in order to buy new ones at a discount. And manufacturers are also very fond of giving additional discounts if you refuse equipment from another company and buy only their product. In general, when purchasing a station for 200 thousand dollars, you can get a discount of up to 10%.
What are the main steps in an office telephone system upgrade project?
It is very important that the modernization takes place almost unnoticed by the customer’s users. Therefore, I repeat, the first thing to do is to audit the existing system and understand what is not satisfactory, what to change and how best to carry out the modernization from a technological point of view. After the audit, we make a proposal with a preliminary design and agree it with the customer. The next stage is the preparation of a working project for the implementation of the station. It is necessary to draw up a numbering plan and provide for everything in order to spend one or two days directly on installing the station. This usually happens on weekends so as not to distract users from their work. At the same time, we order the necessary equipment from the manufacturer. In our laboratory it is thoroughly tested, and if there is a complex installation, prototyping is also carried out in the laboratory. We deliver ready-made, configured equipment to the customer; all that remains is to install and turn it on. We can do this at night, on weekends, at any time convenient for the customer. You can switch users in batches, that is, when the old and new stations operate simultaneously, users switch gradually, in groups, to the new station, and then the old equipment is turned off and removed. All this is described in detail in the working draft.
Naturally, we undertake the training of customer telephone engineers. It is also very helpful to provide user training so that they understand how the new station can improve their productivity. It is more convenient to conduct training in our office. Difficulties may arise at the customer’s site due to the fact that, for example, there is no conference room or there is a lack of necessary equipment. For users, training usually lasts one day.
What problems and pitfalls are most common?
One of the most serious problems when putting new stations into operation, as I have already said, is interaction with the telecom operator. The fact is that the enterprise and the operator may have different alarm settings. In this case, you can spend a long time looking for the cause inside the corporate network, although in fact you need to change the settings on the communication center. This requires working with engineers at the city station. In general, switching the external flow is the most important part, since much depends not on the integrator, but on another organization. It is difficult to predict and provide for everything here. It happens that at first everything goes smoothly, the equipment turned on and worked perfectly, and then, a week later, it turns out that some calls are not going through because the routing at the city station is blocked. Therefore, it is better to connect modern PBXs through converters that raise the signal level, correct noise, and so on.
In addition, it is sometimes very difficult to obtain the necessary data from the customer. It happens that the installation is already underway, but the number plan has not been drawn up, there is no list of user connection groups, or a list of services that need to be provided to specific users. In other words, the enterprise IT staff does not really know how the telephone system works and what is needed from it. Functionality Modern stations have a lot and you can activate anything, the main thing is that they are in demand.
Of course, the average modern user does not need such broad functionality of new PBXs. But the fact is that it is easier for the manufacturer to implement all the functions at once than to install special software for each solution option. Therefore, manufacturers sell a product that contains all the functions, but new ports and new functionality are opened only depending on the license. When purchasing, you don’t have to pay for all the functionality, but it potentially already exists. And when during operation it becomes clear that a certain function is needed, a license is simply purchased.
In addition, in the first month after the launch of the system, we make sure to “monitor” the situation. The fact is that in many companies, IT specialists, if something doesn’t work, have neither the time nor the desire to call the support service and figure it out. And then to the question “How does the system work?” - you can hear: “Disgusting!” And if the customer had called, then perhaps the misunderstanding would have been resolved within a minute. Therefore, we try to prevent such situations. Often, a company signs a service contract. Whether the boards burn out, the phones break down, or the customer’s administrator has unsuccessfully changed the settings - all this requires our intervention.
What is the current standard service life for new equipment?
The equipment itself can function normally for 10-15 years. But during such a time, a lot can change in the company: tasks, number of employees, etc. Therefore, the station must be designed to increase capacity (adding subscribers) - and this must be taken into account when implementing the project. During operation, software may be upgraded, individual boards may be replaced, but the chassis, as a rule, is not changed during this period.
How relevant is it for Russian enterprises to link the telephone system with the rest of the IT and engineering systems of the office?
This is very important when upgrading a system from scratch. If you use IP telephony from the very beginning, you can halve the number of SCS ports by connecting both a computer and a telephone to one outlet. Now everyone is trying to build a new office in a single complex and include all necessary communications in capital costs. Many organizations want all equipment to communicate with each other. They already understand that sooner or later it will come in handy, even if it won’t be used right away.
