Dual SIM technology - everything you need to know
Have you ever wondered what is so special about smartphones with two cards?
What benefits does Dual SIM technology have, how does it work and what benefits can it provide?
Maybe you already know these things, but are you wondering what is Dual SIM standby and how is it different from active?
If you want answers to these questions, or see a list of the best dual-card smartphones, read this article.
What is a Dual SIM smartphone
A device that can hold two cards is called Dual SIM. If you have two cards, this means that your smartphone can use them to make or receive phone calls.
Why Dual SIM Smartphones Are Useful
For some people, Dual SIM devices can be extremely useful. For example, business people typically have one phone number for work and one for personal life.
An entrepreneur can either use two different smartphones, or use a phone with both active phone numbers on it. Having only one smartphone is, of course, easier than constantly carrying two at once.
Another common situation in which you might be interested in this technology is when one card is used for calls and the other for the Internet.
For example, some mobile operators have good plans for voice calls, but expensive ones for internet access.
Then having a Dual SIM smartphone, you can combine two different operators and get cheaper bills overall.
What Dual SIM smartphones are there?
If you decide to buy a Dual SIM smartphone, you should know that there are several types of implementations and some of them are better than others. The most common types are:
- Dual SIM passive is the weakest implementation and is used mainly on cheap phones, not smartphones. This passive mode is capable of using two different cards, but only one of them can be active. This means that if one works, then the other doesn’t. In order to use the second one, you need to activate it manually, and the first one will be automatically disabled.
- Dual SIM active - this implementation allows you to make phone calls from any card and receive calls from any card at the same time. Having this technology, you can conduct a conversation from one card, and the other can receive calls, messages and data from the Internet. For example, if you have a call on the first card, and receive another one on the second, you will be notified about this. These devices have two radio transmitters, one for each card. This means that they consume more power than Single technology smartphones and are more expensive, resulting in a higher purchase price.
- Dual SIM dual standby is a hybrid between two Standby and Dual SIM dual active. Dual standby mode can work with two cards active at the same time, but they are only active while the smartphone is in standby mode. Then you can make and receive calls to any number. When you make a phone call to one of the numbers, the other becomes inactive. This is not a perfect solution, but it is a less expensive option and very common.
Is it possible to use the Internet on both cards in a Dual SIM smartphone?
Answer: yes, but it depends on the manufacturer you choose. Manufacturers look at how much it will cost them and their profitability.
It is inexpensive to create devices that support fourth- and second-generation data connections.
4G + 2G modes can be combined and use the same spectrum.
However, if you want a Dual SIM smartphone that supports 4G on one card and 3G or 4G on the other, you'll need a processor powerful enough to handle two high-speed data connections simultaneously.
Examples of smartphones Dual SIM double active
Although dual active devices are the best solution, due to their high cost they are not widely used.
The only dual-active smartphone that can easily be found on the counter is ASUS ZenFone 2 ZE551ML.
Examples of smartphones Dual SIM double backup
A good balance between cost and features that they offer, most Dual SIM smartphones on the market today are dual standby.
If you want to buy such a device, here is a list of some good options: Samsung Galaxy S7, LG G5, Huawei Mate 8, Xiaomi Mi 5 Dual, ASUS Zenfone 2 Laser ZE550K, ASUS Zenfone Max ZC550KL, Lenovo Vibe X3, Huawei P8 Lite, OnePlus X and Lumia 650.
"Dual devices" can be very useful in some cases, and manufacturers have noticed that people want such devices. As a result, more and more of them are produced every year. However, as you've seen in this guide, not everything works alone, and some implementations are better than others.
Tell us what kind of experience you've had with this technology and what you think about it in the comments below. Good luck.
Article about Dual SIM phone, operating modes.
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Phone with two SIM cards. Operating modes, characteristics
A phone with two SIM cards is one device that includes two phones.
Dual SIM phone
The design of the phone includes two niches for placing SIM cards, two transceivers, two separate numbers, and work with two different operators.
The workflow is based on the sequential connection of SIM cards for incoming and outgoing calls and messages.
The phone has a special switch key. New generation smartphones have GSM1, GSM2 keys for selecting an operator line. You can set the number of the desired operator manually. The phone's memory stores a list of contacts from two operators.
Affiliation with a particular provider is indicated by the highlighting of the contact number or an icon with a number or letter.
The possibilities and growing popularity of this type of cellular communication include the following:
- practicality, ease of communication
- inexpensive cost
- systematization of contacts, for example, personal numbers and production numbers
- economical calls over the network within one operator
- using SIM cards from a local operator when traveling and on business trips
There are several modes of operation of phones of this kind. Depending on this, the phone names will include the selected operating mode.
Systematization of modes of 2-sim card phones
The following modes are distinguished:
- 2Sim Dual Bands or Dual Standby, dual standby mode
- Pseudo-Dual, pseudo mode
- Dual SIM Dual Active, active mode
- Dual Talk, communication mode
Take a closer look at each of the modes.
Dual standby mode (2Sim Dual Bands) or (Dual Standby)
This mode is one of the most popular among mobile phones with a dual SIM card. The phone uses one transceiver that receives signals from cellular operator stations. Two SIM cards are in standby mode. While communicating on one SIM card, incoming calls and messages to the other card go into voicemail mode or a message is sent that the subscriber’s device is out of range.
The latest phone models, designed on the basis of MediaTek chips, have the function of automatically changing the SIM card, with one radio transmitting device.
The advantages of a phone with this mode include economical energy consumption compared to devices that support one SIM card. The disadvantages include the fact that the first SIM card supports 2G/3G networks, and the second only 2G networks, as well as the inability to make calls simultaneously from two cards.
Pseudo-Dual
The mode supports two SIM cards, but one of them is real, inserted into a slot on the phone body, and the other is Internet (virtual). The virtual card is supported by the mobile operator.
The mode is not entirely effective, since the phone needs to be rebooted to switch numbers, and only one phone remains in working mode. The mode has not gained much popularity among phone manufacturers and users.
Active mode (Dual SIM Dual Active)
A phone that supports active mode is two-modular, i.e. has two radio transmitting devices. The modules switch among themselves during a conversation and work in parallel. A special key is used for manual switching. Currently, many series of phones running on the Android system platform adhere to this mode. The disadvantages include increased energy costs, large geometric parameters of the phone, and high cost due to increased demand.
Communication mode (Dual Talk)
In practice, this mode is communication in a conference call. A phone that uses talk mode uses two SIM cards, two EDGE transceivers, and allows you to talk with two interlocutors at the same time. The phone mode provides voice communication, messaging, faxing, and Internet access, in the most modern EGSM900/1800 standards.
There are still few phones on the market that provide Dual Talk mode. The most famous of them is the LG GX500 series phone.
We hope that reviewing the modes will help you choose a convenient phone!
Video: Nokia 230 Dual SIM review
When Apple announced the new iPhones XS, XS Max and XR on September 12, one feature captured the attention of international travelers and multi-phone owners: dual SIM cards.
If the processor is the brain of your phone, the SIM card or subscriber identity module is its soul, the tiny little chip that stores your phone number and connects you to the cellular network. Essentially, this is what makes your phone a phone.
If you've ever wanted two phone lines on one device, Apple's new Dual SIM Dual Standby technology could be life-changing (for Android users, this is no longer a new thing). It may be more practical to have two phone numbers on one phone - one for business and one for personal use. And it becomes much easier and cheaper to use your own phone when traveling abroad.
Although the iOS 12.1 beta contains the most important component of the technology - eSIM remote provisioning, Apple will make it available to the public later this fall. Of course, this won't be a deciding factor for the vast majority of people eyeing a new iPhone in 2018, but the debut of the iPhone XS, XS Max and XR heralds a new era of dual-SIM phones.
We don't yet know all the details about how, when and where Apple's Dual-SIM feature will work. But based on our current understanding of how the technology will be implemented, there are some limitations. So far, here's what we know about Apple's dual SIM card—and what it means for the three new iPhone models.
What is a dual-sim in terms of Apple?
The 2018 iPhone will allow you to have two different phone numbers on one phone. You will be able to make and receive calls, as well as send and receive SMS to any of the numbers.Why do I need a dual SIM phone?
There are two main advantages. You can have two different phone numbers - for example, one for business and one for personal use - without having to carry two phones. And when traveling abroad, dual SIM card slots make it easy to add a local number to your phone to avoid costly international roaming charges.
Will the iPhone have both eSIM and plastic SIM cards?
Yes. The new iPhones will have a traditional plastic SIM card, a familiar SIM card that identifies you to your carrier network, and an eSIM, the more modern software equivalent.And here's the kicker - the eSIM can hold multiple phone numbers, which you can add, remove and customize directly from your iPhone's settings. The plastic SIM card can only be physically removed or replaced.
In theory, as soon as eSIM technology begins to be widely supported by mobile operators internationally, Apple could completely abandon the plastic SIM card. For now, 2018 iPhones have both plastic SIMs and eSIMs, and Apple has both covered.
What is Dual SIM Dual Standby?
Apple's dual SIM card system is called Dual SIM Dual Standby. This means that the new iPhones can manage two phone lines at the same time - calls received on either of them will be sent to your phone, and you can easily make calls and send SMS from any of your numbers without changing SIM cards.Please note that you will not be able to send and receive data on both lines at the same time; If one line is on, incoming calls to the other number will go to voicemail.
What is the difference between eSIM and Apple SIM?
Originally known as Apple SIM, the first version of Apple's soft SIM card appeared on the LTE-compatible iPad and Apple Watch Series 3. Analysts say the technology is the same at a fundamental level, but iOS 12 could bring improvements to the user interface.Can I add numbers from different operators?
Yes. Apple says you can add numbers from two different carriers - as long as your iPhone isn't locked to one carrier. And this is the main point. If your phone is linked, both numbers must be from the same operator. And if your first SIM card is provided by a CDMA carrier such as Verizon, Sprint, US Cellular, Boost and Virgin, your second SIM card will not support CDMA.Can I use eSIM on an operator-locked iPhone?
When you buy an iPhone directly from Apple, online or from a partner store, it is untethered—meaning it can be set up and activated on any carrier's network.But if your phone is tethered, your options are much more limited. The linked phone has a software code that prevents you from using it on another operator's network. An unlinked phone does not have blocking software; it happens that some craftsmen call previously linked phones from the operator. Once the device is unlocked, you can change the SIM card to a SIM card from any other operator. Most carriers require you to pay for your phone in full before they will unlock it, and other restrictions may apply.
An unlocked phone with a plastic SIM card requires a new plastic SIM card to move to a new operator. On the other hand, eSIM can accommodate multiple SIM profiles from multiple operators. So far, eSIM has not received much support from telecom operators, who are understandably wary of making it easier for customers to switch to other operators.
When will Apple launch its eSIM feature?
Apple is enabling eSIM features in the iOS 12.1 update, which is currently in beta. At first, of course, everything will work only in the USA. US carriers will need to provide a QR code before the line can be activated with an eSIM, which will likely coincide with the public release of iOS 12.1. According to the German site iPhone-Ticker.de, some Deutsche Telekom users have reportedly already used the eSIM to add a second number to their iPhone.How to set up eSIM on a new iPhone?
Owners of 2018 iPhone models will be able to access eSIM through the smartphone settings. According to an Apple spokesperson, you'll be able to use your phone's camera to scan a carrier QR code, which will initiate the second number activation process. Next, iOS will let you choose a default number for calls and SMS, choose a label for each number, and so on.Apple has outlined the eSIM setup process step-by-step on its support site.
Is it possible to rewrite an eSIM?
eSIM can be rewritten and you can choose a tariff from any operator that supports the technology.Which operators support eSIM technology?
Apple says eSIM works in 16 countries: in the US, AT&T, T-Mobile and Verizon currently support the technology. A Sprint spokesperson said the company will begin supporting the feature in the near future.) Internationally, participating carriers currently include Truphone, Bell, EE, GigSky, Vodafone, Jio, Airtel and Deutsche Telekom.At a conference on September 12, Apple announced that more carriers will add support throughout the fall and next year.
Are there other phones with Dual SIM technology? And doesn't Google Pixel 2 have an eSIM?
There are many phones that can handle two SIM cards at the same time, but only a few support eSIM so far. The Google Pixel 2 has an eSIM - but it's primarily for use with Google's Project Fi cellular service.Do I have to get permission from my primary carrier to add a second phone number?
No, you do not need permission to add a second phone number. In fact, the main benefit of eSIM is that you don't even have to go to the store to activate the second number - it can all be done remotely.Why doesn't eSIM work in China?
Apple has announced a special edition of the new iPhones for China, which will feature two plastic SIM card slots instead of eSIM technology. According to Neil Shah, who covers mobile technologies for Counterpoint Research, Dual-SIM technology is popular in China, but very few operators have introduced support for eSIM technology.
What about Russia?
According to representatives of the big four cellular operators operating in Russia, they are all testing work with eSIM in their networks.A representative of the Ministry of Telecom and Mass Communications said that the department would welcome the introduction of eSIM by Russian operators, however, strict compliance with the law, including the identification of subscribers, is required. To date, companies have not contacted the ministry regarding changes to the legal framework.
What is Dual Standby:
When you designate phones and GSM communication equipment with the Dual band brand, you can be sure that they are intended for two frequency ranges. The first such cell phones and equipment were developed in 1997. by Motorola. They provide the ability to receive and transmit mobile signals at 900 and 1800 MHz frequencies, allowing operators to support both cellular standards, which increases their revenue and makes them more attractive to subscribers in different countries.
The need for several ranges is explained by their differing advantages. For example, 1800 MHz is more convenient to use in large cities and densely populated conglomerates, unloading traffic, because the wavelength is shorter and the signal penetration is higher. And 900 MHz is convenient to use outside the city, in large areas, since the wavelength is longer, and, accordingly, more energy.
Equipment equipped with Dual band allows the provision of communication services uninterruptedly, without being distracted by switching between two main bands, increasing capacity and optimizing revenues by introducing new additional services. All Motorola phones and most phones from other manufacturers have these devices.
GSM standard phones can be not only dual-, but also triple- or even quad-band, which allows them to be used in more countries around the world, because the frequency ranges of, for example, the USA and Europe differ significantly. We can conclude that the invention of the Dual band was caused by the need to develop mobile communications and became another milestone on the path of progress.
What Dual Standby gives:
Dual SIM Dual Standby: what does it come with?
BlogsAftorr 05.10.2011 at 23:29
If you type “dual sim UAH” into Google, you risk getting lost in a sea of offers from a wide variety of Chinese and other mobile phones. Usually we are talking about Dual Standby - two cards, as it were, on the network through one radio channel. What can be squeezed out of this?
Real Indians: two channels simultaneously in talk mode
And sometimes three. There is a device for sale named after merciless Chinese craftsmen, which has three GSM radio channels, divided in turn into two SIM cards in standby mode. Total - that's right, you can put as many as SIX SIM cards under the battery and feel like a Terminator. About half a day until the battery runs out. But there are also three of them in the set, so with a pocket full of batteries you can look down on the crowd.
Mobile phones with two separate GSM paths cost one and a half times more than analogues with one channel. How justified such a scheme is - everyone decides for themselves based on the results of use; two channels eat up the battery faster, but are perfect for people with split personalities, allowing you to have two conversations on different numbers at the same time. No matter how hard I tried, I couldn’t find a use for these two channels in a regular mobile phone. But in smartphones it’s no different.
Hybrids include CDMA+GSM mobile phones, where different channels also operate in parallel. Well, for maniacs there is also CDMA + 2xGSM and so on.
The soldier is sleeping, the service is in progress: two SIM cards in standby mode, one channel
A huge disadvantage of this option is that during a conversation on one of your numbers, the second one remains unavailable. This is what he reports to his disgruntled acquaintances: they say, your subscriber is not in touch, he has fallen into the ground. Acquaintances then get offended - why, they say, turned off the mobile phone. But in fact, he was just talking on a different SIM card.
This means that the first thing you need to do, having put two cards into such a phone, is to set up conditional forwarding “if unavailable” from the first number to the second, and from the second to the first, through the operator’s menu. After this, friends who called at the wrong time will receive a normal “the caller is talking” signal, and you will see who is calling you.
The second disadvantage is related to the way in which two SIM cards “share” one radio channel. If you show it on your fingers, it looks something like this:
1. The first SIM card is registered in the network of the first operator. This needs to be done at intervals, say, once every 5 minutes (the figure is completely arbitrary, for real values - see the GSM specification). So, for the next 5 minutes, the first operator believes that your first card number is available at this address.
2. The second SIM card is immediately registered - in the network of a different or the same operator, it doesn’t matter. The operator generally does not care that two SIM cards are registered on one device, since he will still encode the data not for the device, but for the digital key of a specific SIM card.
3. After 5 minutes, the process is repeated, as a result of which the operator(s) are confident that both cards are online.
So, the registration process is an exchange of data. It takes very little time, but according to the law of meanness, they can call you on the number of the first SIM card exactly at the moment when the second one is registered on the network. And the first SIM card will not be able to answer the operator, giving the result “the subscriber is not online.”
This can also be treated by redirecting, but don’t be surprised if a couple of times a week someone manages to “redirect” out of the blue. It just happened right when registering another card.
But my “double standby” LG does not require charging for weeks. And at the same time, it was not announced as a super-economical phone, it just happened that way. I'm afraid that with an option with two simultaneously operating channels this would be impossible.
With the Internet in life: smartphones
So, I have “just a phone” with two cards – Beeline and MTS. Not for some kind of savings, but in order to be in touch: holes in the coverage of Kyivstar and MTS rarely coincide. Well, before the Kievstarization of the Beeline, MTS was even more justified as a safety net.
But I also have a simple smartphone that desperately needs the Internet. Who gives us smart internet? That's right, Ukrtelecom. His card is in the smartphone.
But the prospect of carrying a bunch of devices in my pockets is somehow depressing. After all, I bought a “dual SIM” phone so that I wouldn’t have to carry an extra phone. And here you are, again, a crowd of gadgets.
And I almost fell for it, out of habit I almost bought an Android smartphone with two SIM cards in standby mode. Now, finally, sensible ones have appeared - with Android 2.3+, on MTK 6573 or Qualcomm 7227 processors. But I realized in time that such a device simply does not make sense.
Judge for yourself: the smartphone is somehow constantly connected to the Internet. Receives the notifications I need, keeps in touch my SIP number, working Jabber, and so on. This means that the only communication channel is almost constantly occupied by an Internet session, and you can only get through to an Internet card: the second one will simply “dangle” under the lid, becoming accessible only if the Internet has ended.
Of course, if you turn on the Internet session on your smartphone only when necessary and manually, two cards will work in standby mode. But this is still not the most common mode of use of such devices.
So for “smartness” you will have to look for a more expensive two-channel device - a reviewer recently ran through here. There you can enjoy receiving a call to the second number, while the first card shows Yandex traffic jams from the Internet.
Two technologies for two SIM cards September 29th, 2016
Smartphones with support for two SIM cards have become so widespread over the past few years that it is now easy to buy such a gadget for every taste and budget, from simple dialers to flagships. But almost all of them work with SIM cards in alternating (DSDS) mode, and to find a device in which both SIM cards work simultaneously (DSDA), you will have to try.
I knew the basic principles of smartphone operation in both modes, but still, it turned out there were interesting points there. Look...
DSDS or DSDA?
In the vast majority of modern communication gadgets, two SIM cards operate in DSDS (Dual SIM Dual Standby) mode, which is usually called “alternating” in Russian. The operating principle of DSDS is that both SIM cards use the same radio module. Smartphones with DSDS can have either one or two IMEI (International Mobile Equipment Identity) numbers, but the presence of a second number is not required according to the rules of the GSM Association.
The ability to receive calls to any of the SIM cards is due to the fact that in standby mode, SIM cards can “communicate” with the network simultaneously thanks to time multiplexing. If a call arrives on one of the SIM cards, the second one is simply turned off - at that moment you can neither call nor send a message to it.
Another disadvantage of DSDS is the lower quality of communication compared to phones with a single SIM card. The radio module constantly has to carry a double load and, as a rule, “communicate” with different base stations of different operators. For the same reasons, everything is not so smooth with the mobile Internet: it is almost impossible to obtain the maximum data transfer speed on DSDS devices.
Of course, in reality, everything is not so bad: DSDS smartphones usually cost less and last longer on a single battery charge, and modern models are quite capable of providing decent call quality.
But if you want to get the most reliable “dual SIM” gadget, you need to look among devices that support DSDA (Dual SIM Dual Active) mode. Such smartphones are equipped with two radio modules independent of each other, each of which must have its own IMEI. Thanks to the presence of two radio modules, communication is usually more stable. Plus, they allow you to simultaneously receive calls on both SIM cards or talk on the phone and at the same time view the necessary information on the Internet. But such gadgets consume more energy - this feature is worth keeping in mind. Also, the second radio module in DSDA smartphones is often limited to 2G or 3G networks, but this is done to reduce the cost of the device and increase its autonomy.
By the way, I once saw almost five-SIM phones on Chinese sites.
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