What does dual sim mean? What is Dual Sim on a phone? Switching air distribution modes

We don’t remember who invented the combined slots, but there is reason to believe that the author of this horror is a Chinese company with a name starting with the letter H. However, it shouldn’t be blamed for the popularization of this strange solution: the idea was quickly picked up by dozens of other manufacturers, and now a large Some smartphones do not allow you to use two SIM cards and a memory card at the same time.

Manufacturers can understand: combined slots (SIM+SIM or SIM+MicroSD to choose from) are cheaper to produce, and they also take up less space in the case than three separate slots at once. What’s important: we’ll save on the extra slot by installing a slightly more capacious battery.

In general, it is possible to understand them, but it is unlikely to forgive them. Because combination slots are extremely inconvenient. Especially if the device does not have 64 or 128 GB of memory, like flagships, but only 16. Of these, another 3-4 are consumed by the system, and the user who needs two SIM cards is left with a measly 10-plus “gigs” . Well, where is this good? That's right, nowhere. And that’s why we have collected in this review several smartphones of different classes that offer separate slots for two SIM cards and a MicroSD flash drive.

(27,990 rubles)

An interesting upper-middle class smartphone in a glass case, with a USB Type-C port, a high-quality AMOLED screen and a good camera. A little expensive, of course, compared to analogues, if you compare the characteristics “on paper”. However, the high price is justified by some pleasant aspects, for example, the presence of protection against water and dust according to the IP68 standard and those separate slots. If you still want to save money, look towards the Galaxy A5 2017 - it is a little simpler and cheaper. But on the Galaxy A3 2017, if you need exactly three slots, you shouldn’t look: there are two of them.

(12,990 rubles)

A mid-level device from Nokia, revived this year. Pros: the correct slots, of course, as well as Android with guaranteed updates for several years and a nice metal case. The model does not have very striking features, but overall it is a good workhorse for those who still believe in Nokia. And yes, you can consider it as an alternative - this device is simpler in all respects, but it still has three card slots.

(12,990 rubles)

Motorola employs the right people: that they are in an embrace with the G5 Plus, that the Moto E series devices use separate slots for SIM cards and MicroSD. We included the Moto E Plus in this review, since this device, in addition to everything else, also has a powerful battery - 5000 mAh. The case is metal, the chipset... But with the chipset everything is complicated: a simpler version with the MediaTek platform is supplied to Russia, while a more powerful version with the Qualcomm chipset is supplied to some other countries. If you are visiting the USA, buy Moto E Plus there.

(16,990 rubles)

A middle-class frameless phone with an 18:9 aspect ratio, reminiscent of two flagship smartphones of the Korean company - V30 and G6. This is what makes it interesting, being otherwise a fairly simple solution. There isn't even an NFC chip. However, for those who want to get NFC and a larger amount of RAM (3 instead of 2 GB), there is a slightly more expensive option.

(21,990 rubles)

Previously, Sony used the correct “three-card” layout in almost all of its models, but recently the Japanese have relaxed somewhat. However, the Xperia XA1 is a pleasant exception; there are exactly three slots. The smartphone also has a 2300 mAh battery, a 23-megapixel camera, a 5-inch HD screen and an average MediaTek chipset. But the main thing, of course, is the so-called “Sony style”: the design of the Xperia XA1 really differs from smartphones from other manufacturers, which can often be confused with each other.

(9,990 rubles)

In recent years, Xiaomi has persistently followed the “SIM+SIM or SIM+MicroSD” rule, but made an exception with the Redmi Note 5A model. A simple version of this device is supplied to Russia, that is, without a fingerprint scanner, with cameras of average quality and 16 GB of internal memory. But it is quite cheap, being one of the most affordable smartphones in the Xiaomi line.

(13,900 rubles) /

And again, a device with a 5000 mAh battery - that is, “long-lasting”. On the one hand, this is one of the simplest devices in the Zenfone 4 family, on the other hand, it has a lot of interesting things. Here you have the mentioned battery, and three slots, and a dual rear camera. The principle of its operation is approximately the same as that of LG models - one wide-angle lens, which allows you to capture large objects from a short distance.

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 seem to be 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 is out.

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.

p.s. Want your Samsung Galaxy Mini to charge 15% slower? Disable automatic screen rotation in settings! Yeah, I'm freaking out myself, but it works.

Phones with support for dual SIM cards appeared relatively recently, just like . Moreover, just a few years ago, the only representatives of “dual-sim systems” were Chinese replicas of well-known terminals. However, most modern manufacturers did not want to miss such a promising market and presented their own solutions in this segment.

As a rule, phones that support simultaneous operation of two SIM cards are chosen by people who need to separate business and work contacts. They have to make calls much more often, so you need to approach the choice of phone consciously. But what are the main types of DualSIM devices that can be found on sale? There are three basic “formats”:

Dual SIM Standby;
Dual SIM Active;
Dual SIM Dual Standby.

That's what we'll talk about today.

Dual SIM Standby

This technology appeared very first. You should not expect outstanding performance from it, since all its differences from classic phones consist in the presence of two slots for SIM cards. This means that there will always be only one card online. And, if you want to make a call from another, you will have to turn off the first one. For a long time, to change the active card, you had to reboot the phone. Many people did not like this solution, and the manufacturers added the ability to switch cards from the menu.

Of course, Dual SIM Standby has a significant drawback - the ability to use only one card at a time. However, many customers only need an occasional call from an additional number. Also, the level of energy consumption is significantly reduced compared to a full-fledged Dual SIM. And the price of the phones themselves is not much higher than conventional “single-wear” devices.

Dual SIM Active

Phones that support this mode have two slots for SIM cards. Moreover, both cards will work simultaneously, both for reception and for conversation, for which it is necessary to contact a direct or other operator. Thus, the owner of such a “tube” will always be “online”.

Often, you can find a combination where one slot supports only GSM networks, while the second slot supports both GSM and UMTS. Such a solution will be convenient for those who always need to have 3G mobile Internet and their permanent number at hand. The disadvantage of phones that support Dual SIM Active is the presence of two radio modules, which significantly increase the price of the phone. But, in addition, the level of energy consumption also increases. Therefore, you should not shave phones with simultaneous operation of two SIM cards if their battery capacity is below 1000 mAh. It is best if this figure exceeds 1200 mAh. Otherwise, you will have to constantly look for an outlet.

Dual SIM Dual Standby

Following the first two types of “dual SIM” phones, a compromise option appeared - Dual SIM Dual Standby. It assumes that the phone has only one radio module. However, both SIM cards will be available for the appointment. The only exceptions are those moments when there is a conversation on one number - then the first one will be offline. This became possible thanks to the operation of the radio module in alternating mode. This approach has made it possible to significantly reduce the cost of DualSIM phones to the level of the middle and even lower price range. In addition, the operating time on a single battery charge has increased significantly.

The most widely used devices are Dual SIM Dual Standby devices, which ensure constant stay “in touch” without the need to overpay extra money for the opportunity to talk with two subscribers at the same time and make transactions.

Before buying a DualSIM phone, you should pay attention to what mode you will use it in. For those who only care about conversations, you should pay attention to the cheapest models with simultaneous operation of two SIM cards in standby mode (or constantly). Well, for those who buy such devices to save on Internet bills, we can advise choosing devices with large touch screens, which have begun to appear on the market like mushrooms after rain. In any case, happy shopping!

The term Dual Sim in a phone or smartphone means support for two SIM cards, one of which you can use, for example, for personal calls, and the second for work. Many modern smartphones support two SIM cards.

It is important to note that there are several types of dual SIM support.

Dual SIM Dual Standby (DSDS) or Dual SIM Standby (DSS)

The essence of this technology is that both SIM cards can be in standby mode at the same time, but making a call is possible only using one of the SIM cards.

What does this look like in practice? A call can be placed on any of the SIM cards, but as soon as you start talking, the second SIM card will automatically become unavailable. If you call it, you will hear a message stating that the subscriber’s phone is turned off or is out of network coverage.

This technology is not suitable for those users who want to receive several calls from different SIM cards at the same time. However, you can enable support for call forwarding from one SIM card to a second.

Dual SIM Dual Active (DSDA)

This is a more interesting technology, since, unlike Dual SIM Dual Standby, it allows you to receive calls simultaneously from two SIM cards. And all because in this case two radio modules independent of each other are used.

This option is more convenient and versatile, however, smartphones with Dual SIM Dual Active technology may be slightly more expensive (not in all cases).

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 10/05/2011 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?