Network cards for computers: what the modern PC equipment market can offer. Wi-Fi network card: types, principle of operation and connection

Let's touch on a topic like the network card of our computer. Let's start with the fact that network cards are different and may differ both in the range of tasks they solve and in the form factor (appearance). The network card is also often called (Ethernet controller, network or NIC (Network Interface Card) adapter).

First of all, let's divide network cards into two large groups:

• External network cards
• Built-in or integrated (onboard)

Let's start with the external ones. From the name itself it follows that network cards of this type are installed into the computer additionally (with a separate expansion card) or as another external device.

First, let's talk about PCI network cards. The abbreviation stands for (Peripheral Component Interconnect) - the interconnection of peripheral components or - an input-output bus for connecting peripheral devices to. These cards are called that because they are installed in one of the PCI slots (connectors). Here they are, in fact:

The PCI interface itself has a peak throughput for the 32-bit version, operating at a frequency of 33.33 MHz at 133 MB/s, the connector voltage consumption is 3.3 or 5V. Serves for installing additional expansion cards into the computer (old video cards, modems, network adapters, TV tuners, various video capture and video conversion cards, etc.).

So, what network cards are installed there? And here are the most common dollars for five or six:

There are adapters of another type - Wi-Fi (for organizing wireless networks).

As you can see, the connection interface is the same (PCI), but the operating principle is different.

Now, due to the gradual “withering away” of this interface, network cards of the “Pci Express 1X” form factor are being produced.

This applies to external network cards. There are also built-in (integrated into the motherboard) cards. You can determine the presence of a built-in network by looking at the back wall of the system unit.

Here we can visually observe the output of the integrated network card. One or more information LEDs are installed next to the twisted pair connector, which can be used to indicate the presence of a connection and the general activity of the network.

By the way, using these LEDs you can indirectly get an idea of ​​the performance of the device. Let me explain my point: when the computer is turned on and the network cable (twisted pair) is connected to the card, the LED on it blinks, as they say, in time with the reception (transmission) of information data packets by the adapter to the network.

If the network adapter is not working, the behavior of the indicators may be as follows:

1. None of the LEDs light up at all
2. The LED is constantly "on" (not blinking)
3. The indicator blinks, but absolutely monotonously. The period and amplitude of this “blinking” are the same throughout the entire time

So, take note of such moments. Everything is in the details! :)

From the markings we see that this is an RTL chip (from Realtek) with number 8211BL.

Notes e: built-in solutions, unfortunately, are not reliable. In our organization, for example, failures of integrated network cards happen regularly. I can’t say that often, but consistently. By the way, my work computer (bought half a year ago) literally burned out the network card the other day, which once again strengthened my opinion about the unreliability of integrated components. I had to install an external one.

I want you to take a close look at the following photo:

Here we look inside the network card connector. Do you notice the difference? One connector (on the right in the photo) has four contact pads, and the other (on the left) has eight. Moreover, both cards are designed for network transmission speeds of 100 megabits per second.

What's the catch here? And he, in any case, is present here :) Let's remember what the twisted pair cable itself looks like, with the help of which we laid networks in one of our free lessons.

It is correctly called UTP cable (Unshielded Twisted Pair - unshielded twisted pair). The fact that it is twisted (twisted) we can clearly see from the photo above. Its individual conductors are twisted around each other to improve the noise immunity of the entire cable as a whole.

The designation “unshielded” means that there is no additional protective shield (braid) made of foil or metal over the veins. Again - for better cable protection. And “pair” because the conductors in the cable are twisted in pairs and according to color (white-orange - orange, white-green - green, white-brown - brown, white-blue - blue).

Now - the most important: to ensure data transmission over a network at a speed of 100 megabits per second, you do not need to use all four pairs (eight conductor cores), two pairs (four cores) are enough! Moreover, strictly defined numbers are used: first, second, third And sixth postings

Directly from the RJ-45 connector it looks like this:

According to the above, to ensure a speed of 100 megabits, we use “veins” numbered 1, 2, 3 and 6. Look at the figure above. These are two pairs: orange and green.

Note: Naturally, it is up to us to decide which cores to use when terminating the cable. The main thing to remember is that these should be the 1st, 2nd, 3rd and 6th conductor (for networks with a transmission speed of 100 megabits/s).

Now look again at the photo, which shows a close-up of the computer’s network card connectors. In the right image there are only four contact pads: the first, second, third, the next two are skipped and then... which one? That's right - sixth! :)

When are all eight sites used? In networks with transmission speeds of one Gibabit per second (and higher). This is where all the conductors of the network cable are used to their fullest :)

So, for some reason you and I (or rather, I alone :)) “veered” away from the main topic. What other network cards are there? Let's look at an external adapter for a laptop based on the PCMCIA standard. This is an external expansion card that is inserted into the appropriate slot.

PCMCIA stands for Personal Computer Memory Card International Association. Initially, the standard was developed for memory expansion cards. After some time, the specification was expanded and it became possible to use “PCMCIA” to connect various peripheral devices. As a rule, network cards, modems or hard drives are connected through it.

Imagine an unpleasant picture: your laptop (to the left three times) the card built into it has failed. What to do? The solution is in the photo below:

There are, however, other solutions that are suitable not only for mobile computers, but also for stationary ones. These are USB network cards.

They can be made in different ways, but the principle of their operation does not change. Here, for example, are two such devices in the photo below:

Or even like this, more like a flash drive :)

I was about to end the article here, but... changed my mind! :) I also wanted to tell you about a type of external network cards called server network cards, which are used in high-performance systems and have more advanced (compared to conventional adapters) networking capabilities.

As a rule, they have a standard connection interface - PCI (or its extended version - PCI-X). Here, for example, is a server network card " D-Link DFE-580TX».

As you can see, this is essentially four network adapters combined into one physical device. Each of the four network ports (cards) has its own MAC address (a unique 12-digit physical identifier of any card or other network device). At the same time, the entire group of ports can be assigned one logical identifier (IP address). For the operating system, a group of such cards looks like one virtual card.

Note: MAC (Media Access Control) address is also often called a physical or hardware address (Hardware Address). For example: the MAC address of my network adapter at work is 00-1B-11-B3-C8-82. There cannot be two identical hardware addresses on a network. You can find it out by entering on the command line: ipconfig /all or such a wonderful team using the utility of the same name, like getmac. Getmac will show you all the MAC addresses of all network devices installed on your computer in a very convenient and visual form.

Let's continue. Combining several cards into one becomes possible using the “Port Aggregation” technology (aggregation or port consolidation). Port aggregation means combining several network segments into one with greater performance. When several network ports form one virtual one, its throughput (theoretically) is equal to the performance of an individual port, multiplied by their number.

Server network cards can operate in two main modes. Let's take a closer look at them. Using the software that comes with cards of this class, you can configure each port as “active” (load balancing mode) or reserve any ports to ensure fault tolerance (recovery mode).

The network load sharing (distribution) mode evenly passes network traffic (data flow) through active segments, reducing the overall load on the adapter, and the recovery mode (in the event of a physical connection failure) ensures uninterrupted communication between the network card and the network.

What else is good about a server network card on a computer? Depending on its “sophistication” :) it can implement computational functions (counting and generating checksums of data frames transmitted over the network) in hardware, without adding additional load.

On such adapters, specialized LSIs (Large Integrated Circuits) are installed, which take on a significant part of the work (collision detection, assembly and disassembly of data packets, checking frame checksums and retransmitting damaged packets). Thus, as we have already said, a significant part of the load is removed from the processor, which already has something to do in a server system :)

Moreover, expensive server network cards have their own processor installed. Such cards show very good performance, as they can effectively cope even with heavy loads. The presence of its own processor allows you to install up to one megabyte on them. And this already transfers these products from the category of just network cards to the category of communication network processors.

It is also impossible not to note such a useful feature as self-healing drivers for such devices. What it is? For example, after a network failure, the adapter can independently decide to restart the network card driver, enable a network connection integrity check, or even forcefully disable the failed port.

Network cards are an external device and the computer system unit are installed as an additional expansion. In general, this is reflected in the name itself. PCI network cards should be mentioned at the beginning of the conversation. This indicates the interconnection of peripheral components. Peripheral Component Interconnect means data input/output bus. Peripheral devices connected to the motherboard use this bus. These cards are connected using a PCI connector. They are clearly visible in the photo below.

This PCI interface is interesting because its throughput is peak. It corresponds to the 32-bit variant, which operates at a frequency exceeding 33 MHz and at a speed of 133 MB/second. The voltage used is up to 5 V. PCI is used to connect expansion cards, for example, a modem, video capture cards, network adapters and much more.

But what exactly can be installed there? Adapters that cost about five or six dollars.

Other adapters can organize a wireless network - WI-FI.

That is, devices that perform different functions can be connected to the same interface.

But gradually this interface is losing popularity among developers, and network cards are also being modernized. Now network cards have the Pci Express 1X form factor.

But there are also built-in network cards. They are integrated into the motherboard. If there is a hole on the back of the system unit, highlighted in the picture with a red line, then you have a built-in network card.

This is the output of the network card and visually we can verify its presence.

Signal lights

There are usually information LEDs nearby. They are located near the twisted pair connector. These diodes also indicate whether there is a network and whether there is a connection to it.

In addition, these same diodes can signal the operating status of the device. That is, if the same twisted pair or network cable is connected, then the LED will blink, and it blinks rhythmically, just like information data packets arrive.

If the network adapter is not working, the indicators may show other signals. For example,

• The LED does not blink, but is constantly on,
• blinks, but the rhythm is monotonous,
• doesn't light up at all.

You need to know about this in order to observe and notice problems in time. Not only life consists of little things, but also the work of a computer.

Let's see what the built-in network card looks like when the case cover is opened. We find a familiar connector and a chip not far from it. It is soldered onto the motherboard and it performs the function of a network adapter.

It must be said that integrated network cards are not a reliable device. Very often they fail. And this happens with enviable regularity even on new computers. Therefore, all attention switches to the external network card.

Let's look at the connectors

Here's a new photo below. Look carefully, this is the network card connector. Can you see the difference?

The difference is that there are eight contact pads on one side, and only four on the other. But both cards are capable of a data transfer speed of one hundred megabits/second.

But how so? Something's wrong here

Then let's take a look at the twisted pair cable that we've mentioned so many times. This is a cable and we have already laid a network with its help.

To put it correctly, this is a UTP cable. From English Unshielded Twisted Pair is translated as unshielded twisted pair. Twisted means twisted. This is clearly visible in the photograph. Twisting the conductors provides interference protection throughout the entire cable.

The veins do not have any additional braiding, and that is why the word “unshielded” appeared. And this makes the cable better protected. All conductors included in the cable are twisted in twos, which is why we are talking about a pair. All pairs vary in color. There is white-green - green, white-orange - orange, white-blue - blue, white-brown - brown.

But these pairs, four in number, are not used immediately when transmitting data at a speed of 100 megabits/second. As you guessed, the number eight appears here. But for the mentioned speed, two pairs, that is, four veins, are enough. But what kind of wiring will be used is strictly defined. These are postings numbered 1,2,3 and 6.

This is what these wires look like in an RJ-45 connector.

These numbers correspond to pairs of green and orange. Of course, color here plays only a symbolic role. If you have a different color at numbers 1,2, 3 and 6, then so be it. But the order must be strictly maintained, then the speed will correspond to 100 megabits/second.

Now look again at the network card connectors. This is the photo above. Where there are only four sites, look what they are like. You can easily guess that these are the first, second, third and sixth sites.

But then the question arises, why are there eight wires and when can they all be used? Answer: They will be used at a data transfer rate of one gigabyte/second. And at higher rates, all eight wires are used.

But let's return to the network card. We've already talked about what they are, but we'll talk more.

So, what network cards are there?

For example, let's take a network card for a laptop. Its standard is PCMCIA. Since this is an external board, we will connect it to a special connector. The PCMCIA standard or Personal Computer Memory Card International Association is translated as the international association of computer cards. At first it was used in the production of expansion cards. Now you can connect other peripheral devices, such as network cards, hard drives or modems.

Built-in card replacements

If the built-in card in a laptop suddenly fails, then there is no need to bite your elbows; in the photo below you see an excellent solution to the problem.

Or this is a solution, this device will be useful not only for a laptop, but also for a desktop PC.

These devices are called “USB network cards”. Despite the decision of the external design, their essence as a whole does not change. Other examples of devices can be seen below.

It's too early to say goodbye

We could have ended it here. But no. After all, external network cards are so diverse that it’s worth talking about more.

There is such a type of network card as a server one. It can only be used in advanced and high-performance systems. Of course, we compare it with a regular network adapter. They still have a standard interface. This is enhanced PCI-X or regular PCI.

The picture below shows an example of a server network card.

It is clearly visible that there are four network adapters here. But they are all in one device. And each connector has its own twelve-digit identifier, that is, a MAC address. Although one IP address can be assigned for the entire group of adapters. And the operating system perceives this group of cards as a single whole.

What is a MAC address? This, Media Access Control, translates as media access control. An address is always unique and, of course, there cannot be two identical addresses.

Port aggregation is not easy, and it is possible thanks to Port Aggregation technology. The name stands for the association. And this means that several network segments can be combined into one. This increases productivity. Well, and accordingly, when all network pots are combined into one, then we are talking about the performance of one, that is, a single port. And its power is equal to the number multiplied by the number of these ports.

There are two modes for operation of server network cards. Let's get to know them now. Each card comes with software included. With its help, each of the present ports can be made active or standby.

There is also a mode when network traffic is distributed evenly across active segments. This is a distribution mode and it allows you to reduce the overall load on the adapter. In recovery mode, when the connection suddenly disappears, it restores. That is, the mode ensures uninterrupted communication between the network and the card.

Is it convenient to use the server card on a computer?

It all depends on how complex your PC is. If there are a lot of bells and whistles, then, in order not to load the central processor, the server card can take on some of the functions, for example, counting the sums of data frames. This data is transmitted over the network. It can also generate data.

So what is a network card? The network card is part of the computer's hardware configuration. This device allows us to connect a computer to the network and provides interaction with it. Network cards are often called network interface cards, network adapters, or LAN adapters.

Network cards were originally an additional component that could be purchased and installed on a computer not immediately, but after some time. However, today it has become obvious that network cards are a standard computer component that is installed in most laptops and computers sold.

Often, they are integrated into motherboards or other devices during the manufacturing process. If the card is installed in a computer system, then it detects itself when connected to the network by small flickering LEDs, which are located at the network connector.

Network Card Identification

Any network card must be unique, so they are equipped with an address, which is abbreviated as MAC. Using it, you can identify any computer transmitting data over the network.

What is a wireless network card

Nowadays, with the help of network cards, you can connect computers using a cable (physical) connection or do without it altogether, using the so-called wireless interface. When using a cable connection, you usually choose a standard network port that has an RJ-45 connector. To connect to a wireless network, the use of different physical ports and interfaces is not required.

The principle of operation of a wireless card is quite simple. A wireless modem is responsible for receiving and transmitting data from the Internet. Data from your provider will arrive at the external port (cable input) of the wireless router, after which it will be converted into a radio signal, which will be transmitted over the air via an antenna. If wireless network cards are within range of the router's transmitter, they will receive the signal and then convert it into an electronic signal that the computer can understand.

In any case, besides the fact that the wireless network card does not require physical contact with it, its configuration is no different from the usual one. Both wireless and wired cards currently allow almost the same data transfer speed.

A device such as a network card allows a laptop or computer to work on the Internet and local network via WiFi, connected via USB or via a special cable. The adapter provides a unique address called a MAC that identifies the computer device transmitting packets of information over the network. If you cannot connect with a cable, you can purchase a wireless wifi adapter for your computer equipment.

What is a network card

An element of the hardware configuration of a laptop or computer is called a Network interface controller, which provides the ability to connect to a network, ensuring interaction between devices. Network cards are LAN adapters, NICs, Ethernet adapters or interface cards. Now the Network interface controller is part of the computer package, but previously it was produced separately.

Types of network cards

An Ethernet adapter is designed to connect computer devices to a local network. The Network interface controller, which provides an Internet connection, has the main characteristic of data transfer speed. The NIC uses high-speed interfaces to interface with a computer device. There are 4 design types of computer boards. They all have basic pros and cons.

Types into which microcircuits are divided according to their physical implementation:

• integrated - as the name suggests, built into the motherboard;
• wireless – for bluetooth and WiFi networks;
• internal (separate boards) – connected via PCI, inserted into a PCI-E or ISA slot;
• External network cards for laptops are inexpensive and connect via USB.

Why do you need a network card in a computer?

The main purpose of a network card is to connect computer devices with each other. The Ethernet adapter provides connection to the Internet. If there is no built-in Network interface controller, then USB modems are used, but then the ability to work over the network is reduced. By combining computers, laptops, peripheral devices (scanners, printers, etc.) in one local network, you can exchange data via WiFi within the boundaries of an apartment, house or provider network.

Principle of operation

Some of the functionality of the Network interface controller can be transferred to the central processor or driver. Information is transmitted over the network, which is grouped into data packets. They move from one device to another. There is software and hardware involved in data transfer. NIC refers to hardware. It is responsible for establishing a physical connection between devices. An 8-pin RJ-45 or 15-pin AUI connector is used.

Where is the network card located in the computer?

The network card in the computer is located in the system unit. You can find it by slightly opening the side cover of the system unit. Modern computers are made with an Ethernet interface. The built-in NIC is soldered onto the motherboard. If it is not built-in, then it is inserted into one of the free white slots. Operation and data transfer are carried out using an optical fiber cable connected to the adapter connector.

What does a network card look like?

You can see what a network card looks like in online stores that have photos of devices. Externally, the device looks like a flash drive, and internally it is a small chip or board located near the computer network connector. It is curved on one side. If you do not open the side panel of the system unit, the location of the Network interface controller looks like a socket for connecting a cable.

How to find out your computer's network card

In the Windows operating system, it is not difficult to identify the NIC, which is necessary in case of a malfunction or when replacing. Programmers call such adapters consumables, because they tend to break. The network card for a PC is an important part of the system configuration, so you can use special programs such as “Everest” and “AIDA64” to detect it. You can determine the model name yourself by following the path:

1. Start.
2. Control Panel.
3. System and safety.
4. System.
5. Device Manager.
6. Network adapters.

How to check if a network card is working properly

A broken network card for a computer or a faulty Wi-Fi card will not allow you to access the Internet or local network. Problems with serviceability may be hidden in the system settings (if you have a built-in LAN adapter) or in the tightness of the cable connection (if external). You can try updating the drivers or testing. The check is carried out in the following way:

1. Computer properties.
2. Device Manager.
3. If there are no exclamation marks next to the name of your adapter, then the equipment is detected normally. Contact your provider.

How to install a network card on a computer

Before you decide to purchase a LAN adapter, you need to make sure that the motherboard does not have its equivalent. The NIC can simply be disabled. To enable it, activation in the basic input/output system (BIOS) is required. If it really doesn’t exist, then buy a NIC at a computer store, and then install and connect the network card:

1. Remove the side cover of the system unit.
2. Once you have selected a free space on the motherboard, remove the blank on the back of the unit.
3. Install the NIC, secure with the mounting screw.
4. Connect the cable to the LAN adapter socket.
5. Turn on your computer. Light diodes will flash, indicating the exchange of information with the network.
6. Set up the connection: install the driver for the network card, register the server DNS (dns).

Price

The adapter will cost up to $5. The set of functions can be selected as desired (adapter with higher data transfer speed, 2 SFP ports). You can order a set of adapters through the catalog in specialized computer hardware stores or buy them in an online store (from 299 rubles). In the table below you will find the price of a network card in Moscow.

In the world of technological progress and global computerization, rapidly developing technologies have touched every modern user. Access to the World Wide Web is no longer limited to using just a computer.

Today, in every home, almost all family members, young and old, have one or several different devices with access to the network. In this case, it is very convenient to install a Wi-Fi access point and distribute a signal to any connected equipment. Modern devices such as laptops, tablets, phones have built-in Wi-Fi receivers, making them easy to connect to a network.

A network card, or network adapter, is a component of a computer that determines its interaction with the network. With the exception of outdated device models, many laptops and computers are equipped with a network adapter during production. This provides the ability to connect to the Internet without purchasing a separate item. But, despite the built-in adapter, you can and should purchase an additional external device, expanding the data exchange capabilities.

The network card can be integrated into the motherboard or external. Regardless of the type, it is assigned a Mac address, through which a computer connected to the network is identified.

Wi-Fi network card

The computer can be connected to the Internet physically using a cable connected to the network port of the PC, or wirelessly, which does not require the use of connectors.

A Wi-Fi network card allows the computer to receive a signal from a wireless network. It can be connected to the PCI connector of the motherboard or USB port of a computer, less often to Ethernet (this type of connection is mainly applicable to older devices). A Wi-Fi card plugged into the USB port of a PC or laptop is most convenient in terms of mobility; it can be easily connected to another device if necessary.

In addition to the connection method and appearance, there are differences in the speed and power of the adapter. Some cards can only receive signals, others can also transmit. Adapters equipped with the Soft AP function provide the creation of a Wi-Fi access point.

The range of signal reception and transmission can be carried out over long distances up to hundreds of meters, or limited to a small access area. As in the case of a router, there is no need to use overly powerful network cards for home use, unless, of course, you are going to distribute Wi-Fi to all your neighbors or take over someone else's signal. In addition, the price will depend on the power of the model, and it is not advisable to overpay for a card that will work in a small area. More robust adapter models are applicable in large areas of offices or enterprises.

How the Wi-Fi adapter works

Access to the Internet via a wireless network is achieved through the joint work of a network card and a router or modem. Wi-Fi technology operates on a specific frequency range. Data exchange with the network is carried out through a router or modem, which communicates with the air via radio waves. For the computer to perceive the radio signal, a network card is used, which reads and converts the signal into an electronic one. All devices equipped with an adapter and located within the range of the router’s transmitter will receive the incoming signal. To digitize data for recognition by the device, the adapter is equipped with a microcircuit and special software that controls the operation of the module. For proper operation, the necessary drivers must be installed.

Types of adapters

All adapters are divided into two main categories:

External. Such network devices are connected via the USB port of a computer or laptop. They are not distinguished by high data transfer speeds, but they pleasantly compensate for this disadvantage with their price, which is why they are the most popular today. In appearance, such adapters look like USB drives. To get started, you need to insert the device into a free port and connect to a wireless connection.

Internal, or built-in. Connect to the PCI connector of the motherboard. To install this type of adapter, you will have to remove the cover of the system unit. The built-in network card is larger than the external one. This type of device has good throughput, resulting in high data transfer rates. The price of the issue will be significantly higher than that of external adapters.

There is another version of devices that is not widely used - card devices (Card-Bus). This type of adapter connects to a PC Card slot, if your computer equipment has one.

Wireless network cards can be connected not only to computers and laptops. A separate niche is occupied by external adapters for TVs. They can be either universal or designed for specific models. If your TV is not equipped with a Wi-Fi receiver, but has a corresponding connector, you can purchase an adapter compatible with it to connect it to a network source.

Network card antennas

A device equipped with an external antenna receives the signal better. Of course, the dimensions of the receiver do not always contribute to comfort, so you can choose an adapter with a removable antenna or with a connector where you can insert it if necessary.

When choosing a device, the antenna power must correspond to the conditions of the location where you want to install the network.

The number of antennas affects the speed of information transmission. Models equipped with removable antennas are very convenient if the router is located far away; if necessary, it is possible to install a more powerful radio wave reception structure. External antennas provide greater range.

Installing and configuring a Wi-Fi adapter

Despite the significant differences in network cards in terms of type and type of connection, they are all configured according to a similar principle.

First, you need to physically connect the adapter to the desired connector on your computer or laptop. Windows will detect the new hardware. Although there are always compatible programs in the system set of programs, for correct operation it is better to install drivers from the disk that came with the network device. You can also download the necessary software from the manufacturer's official website. Data exchange through the adapter occurs thanks to the driver, which is why it is better to install software that is suitable specifically for your device model.

After installing the Wi-Fi card, a network connection icon will appear, click on it and in the properties of the wireless network connection, find the TCP/IP Internet protocol. Here you need to enter network parameter settings; you need to find them out by contacting your provider’s technical support and enter them into the fields to fill out. Settings can also be assigned automatically. When you have selected the necessary parameters and access points, all that remains is to assign a Mac address to the card. This task is performed by the network administrator; to do this, call technical support and notify about the adapter change and the need to change the Mac address.

When choosing a network device, pay attention not only to functionality, because you will not use all the capabilities of the card, and the price for a wide range of functions will increase several times. Pay attention to some factors, such as the dimensions of your room in which the Wi-Fi network will be used, the distance between the router and the computer, and the thickness of the walls. The manufacturer also plays a significant role in the reliability of products; it is better to choose a proven one that has proven itself in the quality of its products, of which there are many in the computer equipment market. It is advisable to purchase adapters from the same manufacturer as the router or modem, thereby ensuring better compatibility between the devices.