How many numbers can be stored on a SIM card?

To use the connection of any cellular operator, you need a SIM card - it is used to identify the subscriber on the network. Despite its small size, a small chip installed in a phone or smartphone is a “smart” electronic device. So, you can save contacts and text messages in its memory.

We tell you how many phone numbers fit on a Beeline, MTS, MegaFon, Tele2 SIM card: whether it depends on the operator, how many contacts fit in the SIM card’s memory, and how you can save more contacts.

Import from SIM card

Sometimes it happens that Android does not see the contacts on the SIM card simply because their display is disabled in the settings. In this case, only those stored in the device’s memory are displayed. This is the most common situation and the easiest to resolve. This usually happens when a smartphone falls into the hands of children and they start clicking anywhere.

You can configure this in the phone book:
Open the list of numbers.
Click on the three dots icon - it will open a menu.
Select Contact Filter.
In the list, select “All” to display all entries, both from the SIM card and from the smartphone’s memory. If only “Phone memory” is selected here, then this is the cause of the problem and everything is solved.

In the same menu, you can select “Import/export” and you will be asked to choose where to transfer the list from - select a SIM card. Then you will be asked to choose where to transfer it - select your phone. As a result, the entire list will be transferred to his memory. This can help when data from the SIM card is still not displayed, although it is there.

If this does not help, it is useful to check the problematic SIM card in another slot, or even better, in another phone - most likely, it has failed. After all, this is actually not a piece of plastic, but a complex device with its own processor and memory, although quite reliable. In this case, you will have to contact the operator for a replacement, but in the duplicate, of course, the list will no longer be there.

SIM card and Beeline Moscow phone number, how to save contacts when changing numbers

How can I find out my USB modem number?

You can find out your number using the Beeline USB modem application. In the application, go to the “Account Management” section and select “My Number”. Click the “Find out number” button - after which an SMS message with the phone number of your SIM card will be sent to your modem. A single payment card can be activated from the Beeline USB modem application.

How to find out your mobile phone number?

Your telephone number is indicated in the annex to the Agreement.

You can also determine your number in the following ways:

Using the command to determine your number, dial the combination *110*10#; Call 067410. You will receive a response with a phone number via SMS.

Select a tariff and order a SIM card online on the Beeline website. It's very simple: we will deliver the SIM card to you ourselves, and if you are in doubt about the choice, we will call you and help you make your choice. You can also buy a SIM card at any of our sales offices or dealer showrooms.

When purchasing a Beeline SIM card, you can get a new number, or you can keep the old one by transferring from another operator along with your number.

A new phone number is assigned when you purchase a contract and start working on the network. It is indicated in the annex to the agreement.

Don't be afraid to lose old contacts when purchasing a new number! Connect and by calling your old number, your friends will receive information about your new number in the form of a voice message or SMS.

To keep your old number when switching to Beeline, write a statement at the office or order free delivery of a SIM card by courier. Read more about number porting.

If you can no longer use your SIM card (it's broken or lost), or you need to change your standard SIM card to a micro-SIM or nano-SIM, we will restore it or change it at any of our offices. Learn more about replacing the SIM card.

You can change the owner of the number, temporarily suspend its use, prohibit number identification, etc.

moskva.beeline.ru

How many contacts fit on a Tele2 SIM card

Home > FAQ > How many numbers can fit on a SIM card We have practically not used paper notepads for a long time, and quite rarely, phone books on devices: the first are not very convenient, and the second disappear due to changes or breakdowns of devices. And how many numbers a Tele2 SIM card can hold is a really important question for many. And this is understandable: we change our contact information quite rarely, so this piece of plastic sometimes stays with us for many years.

The Tele2 SIM card can only hold 100 numbers. Additionally, you can use the volume of the device’s phone book and cloud storage.

What volume is available and how to increase it

So how many numbers can a Tele2 SIM card hold? Unfortunately, this operator cannot boast of a large SIM capacity: the memory is designed for only 100 contacts. But we must understand that here the concept of “contact” can be interpreted as “cell”. Accordingly, several numbers of one person, combined under one contact, will occupy only one cell. That is, from “Vasya’s work”, “Vasya’s home” and “Vasya something else” you can make one Vasya, under which all his contact information will appear. Information on how to activate a SIM card on your phone is in another article.

Electronic media is not a bag, and it cannot be stretched: no matter how many contacts were placed on the Tele2 SIM card initially, this maximum will remain for it. But you can always take advantage of additional features. Namely, connect the device to cloud storage and set up archiving or backup of data to it. This could be iCloud, Samsung Cloud, Google or Yandex drives, etc.

Still, you shouldn’t ignore your phone’s address book. Most modern devices have the function of transferring contacts from one to another. Therefore, changing a smartphone does not necessarily involve tedious porting of numbers manually.

You may be wondering, at what age can you get a Tele2 SIM card? We suggest you read about it.

Please note: sometimes we receive strange messages on our phone from strange numbers, so if you want to learn more about them, read the relevant articles:

Cellular lifehacks

Perhaps the most attractive operator in this regard is Yota. You can get a SIM card from her only with unlimited Internet connection for 370 rubles. Which is significantly cheaper than its competitors: the cheapest unlimited package from Beeline costs 900 rubles, from Megafon - 500 rubles, from MTS - 950. Tele2 does not have an unlimited package, but with 30 GB the tariff costs 700 rubles.

Firstly, inexpensive and older models are, in principle, designed in such a way that only one tray - the main one - has access to higher-order communication modules (3G/4G). Thus, a SIM card purchased for working on the Internet should not, a priori, hang out in an additional slot.

By default, by the way, smartphones give priority to the card in the leading slot. Therefore, when connecting a second SIM card, it is worth setting up the operation of the communication modules manually. The manufacturer writes about how to do this on Samsung here, on Motorola - here, on Huawei - here.

Secondly, almost all new smartphone models have advanced SIM modules, where both the first and second slots are connected to 3G/4G. But this does not mean that both cards can simultaneously operate in the same range. One of the two GSM beacons will always work in 2G if the other is 3G/4G. Regardless of the slot. These are hardware limitations.

Cache full

It happens that the phone does not see contacts simply because the cache is full. This is an area of memory where temporary data is stored and accumulates over time. Since the amount of memory is not infinite, over time it simply ceases to be enough for the growing cache. As a result, an error may occur when saving a new name. Of course, saving is not performed in this case. The cache can be cleared, thereby freeing up some of the smartphone's memory. This is a safe procedure, not only is it useful, and it is useful to do it sometimes for different applications, especially those that are used frequently. This will also have a better effect on performance.

To clear the phone book cache, go to your phone settings, in “Applications”. Find “Contacts” there, select this application. In its settings, like all others, there is a “Delete/Clear cache” button, click it. Temporary data is also cleared for other applications. If after this Android does not see the contacts on the SIM card, then the problem is different.

How to see where numbers are saved on Android OS 8

On phones running Android 8, you can see where exactly the contacts are saved (in the SIM card memory or smartphone) as follows:

Tap on the “Contacts” application icon;
Next, click on the button with three vertical dots, which is located on the top right;
Select the “Settings” menu item;
On the next page, tap on the “Contacts to display” option;
Select the source on which you want to check the availability of number locations (for example, SIM 1);
Return to the list. The data whose media you selected earlier will be displayed;

Reset

If the numbers do not appear, and all previous actions have not brought results, you can try resetting the settings. To do this, go to “Settings” – “Backup and reset” – “Reset settings”. On different smartphones and versions of the Android system, the name of this item may differ slightly, but it is not difficult to find.

Remember that some data may be deleted during a reset, so copy photos, music, and anything valuable that you don’t want to lose to your computer in advance.

Such an operation is similar to reinstalling the system on a computer and can also work wonders. Over time, files and applications accumulate on your smartphone, and various settings change. All this ultimately leads, sooner or later, to a drop in performance and noticeable “slowdown” of the device. A factory reset solves many problems, even those that have no apparent cause. This may include contacts on the SIM card.

A way to see where numbers are stored on a phone with Android versions 9 and 10

If you are using modern Android phones, then you will need to follow the steps below. The names of the buttons and the specifics of certain steps may differ on different phone models, but the essence is the same.

Do the following:

Find the “Contacts” application icon on the desktop of your gadget and tap on it;
In the window that then opens, click on the button with three lines located in the left center; Select the menu button that looks like three horizontal lines on the left
On the page that opens, click on the “All contacts” button.
The media on which your contacts are stored will be displayed. Opposite each such medium there will be a number demonstrating how many numbers are stored on this medium;
If you tap on one of these media, you will see a specific list of subscribers stored on this media.

How to restore numbers on a SIM card

Many years ago, when there were no cell phones yet, in every home you could find a notebook in which phone numbers were written down. There were also special directories with telephone numbers, published in almost all cities. In them one could find not only telephone numbers of organizations, but also home numbers of friends, acquaintances, relatives, and colleagues.

In the absence of such a directory, one could make a call to the help desk, give the person’s name and address, and get his phone number. In cellular communications there is no such opportunity, since operators do not have the right to provide personal data of their customers upon a routine request.

When do you need an additional number?

Examples of situations when the second number may be useful to you.

Placing advertisements on websites Buyers will call an additional number if you have posted an advertisement online.
Orders in online stores and deliveries The consultant will contact you for confirmation, and the courier will call upon delivery at the second number - the main one will be hidden.
Dating at events and online The person to whom you left the second number as a contact will be able to contact you about a personal issue or work - then you decide for yourself how interested you are in continuing communication.
Separation of business and personal Colleagues and clients will be able to contact you on the second number, and family and friends – on the main one.
Participation in store loyalty programs A message about a promotion in your favorite store or a call from a consultant will be sent to a second number - you won’t need to share the main one.

Communicate as you please. If you want to keep your main number only for your close circle of contacts, now you know what to do.

In phone memory

The memory of modern smartphones can store a huge number of contacts of various types - these are phone numbers, addresses, and emails. Therefore, the advantage of this method will be the ability to store large amounts of necessary information in one place.

However, this is also the main drawback - all information can be irretrievably lost if the device is lost, its state is reset to factory settings, or the gadget breaks down. If in the first two cases nothing can be restored, then in the latter, in case of repair, the data will be saved.

On a paper notepad

The method is convenient in that all contacts are written in a handwriting that is understandable to the owner.

You can also write down the name in full and with certain notes in a notepad. Phones have a limited number of characters, so sometimes it's difficult to understand abbreviations. For example, you have 2 contacts in your phone called “Lyudmila P”. You know two women with the same name, but P. can mean a hairdresser or just a person's last name. Therefore, a notepad is more convenient in this regard: you can write down the name in detail, avoiding awkwardness and confusion if, for example, you call the wrong person.

However, there are also disadvantages: if you have a huge number of contacts and, say, extensive handwriting, then the notepad will be very thick or there will be several of them, which is not always convenient. In addition, there is a possibility, especially if a person carries notes with him, that he may simply lose them.

How many numbers can fit on a megaphone SIM card?

Tell me how many contacts can fit on a Tele2 SIM card?

Ekaterina, good afternoon! Each operator has its own amount of memory on SIM cards. In particular, on Tele2 you can save no more than 100 phone numbers.

Tell me, what is the size of SIM card memory for other operators?

You can save contacts on your phone in different ways: in the device memory, on a SIM card, in cloud services. We will tell you in a new article which method to choose and how many contacts can fit on the SIM card of MTS, Megafon, Beeline and other operators.

Storing contacts on your phone

The generally accepted method is to record the contact in the phone's memory. It's fast and convenient: modern smartphones have capacious memory and can save thousands of contacts. Moreover, we are talking not only about the phone number, but also about the address, company, home phone and other subscriber data.

The only negative is that if the phone is lost, critically damaged, or accidentally reset to factory settings, all data will disappear. This applies to photos, videos, notes and contacts. That is why this method cannot be considered as the only correct one. You need to make a backup copy on your computer or in a cloud service.

However, according to reviews from those who lost all their contacts along with their phone, nothing bad happens: the phone book fills up again in about a month. The loss can be considered cleaning, because sometimes the hand does not rise to remove some contacts on its own.

Note!

Despite the fact that storing contacts in SIM memory is convenient and universal, it is necessary to take into account the disadvantages of this method. As the main argument in favor of saving contacts on a SIM, most subscribers cite the fact that this method guarantees the safety of data, and phone numbers will be available in different situations.

For example, if you save phone numbers in the phone's memory, then in the event of a software failure of the device, important data will be lost forever. But access to the phone book in the “cloud” is only possible if you have an Internet connection.

It’s difficult to argue with such arguments, but it’s worth considering that contacts saved in the SIM card’s memory also may not become an indispensable storage method in every situation. Thus, a SIM card, like any other electronic device, is not protected from malfunctions and software glitches. Do not forget that if you lose your phone with a SIM card, you will not be able to restore your contacts.

This is why it is important to have a backup. We tell you how to protect yourself if you choose the option of storing and using contacts from the SIM card memory.

If your phone supports memory cards, then copy the contacts to the device memory and save the backup copy to removable media. In any situation, you will have the opportunity to install a memory card in any phone and copy contact information from the phone book from it. If necessary, this method will help if you need to transfer contacts to a new SIM card.

But if you use a smartphone, it is recommended to make a backup copy to your account. Even if you don't use data from the cloud, you will be able to quickly recover important data.

Cloud storage

This method has something in common with the previous one: there is no point in separately storing a phone book on the Internet, but you definitely need to copy it and store it on a server to gain access after the phone is stolen or broken.

Phones running the iOS operating system are integrated with the iCloud cloud service, and contacts are saved there automatically. That's why when you buy a new iPhone, you don't need to rewrite your contacts - they will appear immediately after you sign in to your Apple ID.

With phones running the Android operating system, the most convenient way to save contacts is in the Gmail service. In the Contacts application, you need to find the line “Copy contacts” (or “transfer”), select the copy source - SIM card or phone memory - and copy to your Google account.

Copied contacts can be further processed on the computer in the Gmail interface: add an address, photo, position or any note about the subscriber. Now your contacts are protected: if your phone is lost or broken, they can be easily restored. As a last resort, enter it manually from Google.

Storing data on the server

You can store contacts on the operator’s server on the Internet or on a Google server

(automatically reserves user address books for up to 30 days).

This is 100% possible to save phone numbers. Create an account, copy numbers from your phone memory and set up synchronization. At the right time, you can easily restore the list of Android phones.

How to do it:

open Google Contacts;

click the “+” button in the lower right corner;

add contact, save.

To download contacts to an Android smartphone, just enable synchronization and download the data. If they don't load, do the following:

go to the Gmail service in the “Contacts” section;

reboot your phone, start forced synchronization.

You can install another application or reset all phone settings to factory settings and start syncing from scratch.

Saving contacts on a SIM card

The good old method, which has been working since the days of push-button Nokia. Despite its miniature size, a SIM card is a real mini-computer with a processor, RAM, permanent and rewritable memory. It is in the rewritable memory that contacts are recorded and erased.

When storing information on a SIM card, the question immediately arises: how many contacts does a SIM card hold? The number is different for everyone, but in general the range is from 100 to 200 contacts.

A Tele2 SIM card can only store 100 contacts;
The Megafon SIM card can hold 200 phone numbers;
The Beeline SIM card also has 200;
Old MTS SIM cards include 250 numbers, new ones no more than 200.

Now you know how many rooms can accommodate SIM cards from different operators. Of course, this volume is not enough for a modern active person - according to statistics, an average of 1000 contacts are stored in phone books. This includes unwanted contacts: you also need to allocate a place for them in order to identify them and not pick up the phone, add them to the blacklist.

Why store contacts on a SIM card?

Why, with many modern methods, do many people prefer to store contacts on a SIM card rather than on the Internet? There are such reasons:

Liquidity - quick access to contacts, no need to go online to search for contacts;
Greater data security - it is impossible to send a virus to a SIM card and steal personal data;
If necessary, a SIM card with contacts can be inserted into the simplest phone; it is not necessary to have an expensive smartphone.

When storing contacts on a SIM card, it is important to keep in mind: if you have to change the SIM card, the contacts on it will be lost. Restoring a SIM card allows you to return the money in your account, save the tariff and connected services, but you cannot restore contacts. So this method cannot be considered reliable. However, from a SIM card you can get a copy of your contacts on your phone in just a couple of minutes and copy them to a new SIM card.

Increase memory

One can argue for a long time whether it is more convenient and practical to store contacts on a phone or a SIM card, but there is no definite answer for all subscribers. One of the advantages of using a SIM for a notebook is that you can move it to another phone and get instant access to your contacts.

However, there are also restrictions on recording contacts on a SIM card. So, depending on the card used, not only may there be a smaller number of available numbers, but there may also be a limit on the “contact name” field. The latter is especially true if Cyrillic is used.

A solution in a situation where it is important for the subscriber to use the SIM card’s memory to record contacts may be to clone it. For this purpose, it is possible to use a “blank” with a large amount of memory. The user receives a more capacious notebook and a larger allowed number of characters for the “name” field.

However, it is worth considering that this process is not only expensive, but also complex, and not every SIM card can be cloned. If you use the services of third parties for this, then there is a high probability that in addition to the duplicate you received, a copy of the SIM card may also be in the possession of third parties. Considering that now a mobile number is access to banking services and other resources, this may lead to loss of access to a bank account, or your personal data and personal information.

Source

Summary

You can store phone book contacts in different ways: in the phone memory, in a cloud service, and on a SIM card. Modern SIM cards can accommodate from 100 to 200 contacts.

If you use the methods separately, this does not ensure 100% data security. Only a combination of methods works well: write all contacts to the phone’s memory, export to the cloud - iCloud, Gmail or Dropbox, and copy the most important ones to a SIM card.

Mobile operator subscribers and smartphone owners have many questions regarding the operation of SIM cards. This small chip is used to provide communication services. The card is a truly smart device capable of storing information. The word “information” means contacts from the phone book, as well as SMS messages.

Story

The first cell phones were significantly different from modern gadgets, and SIM cards were not required to use them. The serial number of the device was used to identify the subscriber, and this presented certain difficulties. The use of communication services was clearly linked to the subscriber's device, and changing it as easily as is now available was impossible.

With the advent of GSM communications, everything changed. IMEI began to be used to identify a device on the network, and SIM cards were used to bind to a cellular operator. It is worth noting that these were not the same cards as we are used to seeing them, and which many call ordinary.

The first SIM cards, which are called full-size, had a format completely identical to the now familiar bank card. However, what they have in common with more modern formats is that they also have a chip that is completely similar in essence to modern ones.

Types of SIM cards and their features

Do not confuse a SIM card with a MicroSD card. The first is a chip for storing numbers and making calls. The second one allows you to store multimedia data and is also inserted into a smartphone.

Of course, every person is concerned about the answer to the question: “What is the difference between SIM cards, and what types are there?” A table that will demonstrate the differences between SIM cards will help answer the question.

What is the difference between SIM and microSD?

A memory card and a SIM card are completely different devices, and the memory blocks on them are also different.

A SIM card is a microcomputer containing the following components:

CPU;
RAM;
permanent memory ROM, which stores data about the SIM card (ROM cannot be overwritten);
rewritable EEPROM memory (which can store contact numbers).

What SIM cards do operators use?

Russian users know SIM cards by their MiniSIM format. It is the one that is used most often. Mobile operators continue to issue such cards, despite the fact that almost all smartphones support NanoSIM.

In recent years, operators have been selling universal SIM cards. The subscriber can independently remove the SIM card of the required size from the plastic case.

What to do if the SIM card cannot be inserted into the phone

Since there are several types of SIM cards, the corresponding trays in mobile phones differ. For many years there was no other standard other than Mini-SIM. But time passed, and manufacturers tried to reduce the information chip as much as possible.

By 2021, almost all smartphones will have a NanoSIM tray. But what to do if the SIM card does not fit into this connector. Output 2:

Contact the operator's office to replace the card with a newer one.
Trim by hand.

It is recommended to use the first option. In this case, the employee of the communication store will replace it free of charge and give you a universal SIM card. The plastic case will already have cutouts made for standards from MiniSIM to NanoSIM.

If you can’t go to the office, you can adjust the SIM card to the size of the tray yourself. But first you should find out what type of SIM cards the connector is designed for. For maximum efficiency, it is recommended to place the chip that needs to be cut and the one that corresponds to the desired size next to each other. This way you can perfectly fit the card to the required dimensions. You can cut the SIM card with regular scissors or a cutter. The main thing is not to touch the golden chip itself.

Should you be afraid of surveillance?

It should be understood that we are not talking about total surveillance of each subscriber, since there is not enough equipment or employees for this. Basically, such information is stored anonymously in a special array. Data about a specific subscriber is collected only upon an official request from law enforcement agencies.

Anonymized information is collected and automatically sorted by various filters. This allows you to create survey groups and offer clients favorable service conditions.

Based on data collected by mobile operators, it is possible to understand where the population needs additional shops, hospitals or schools. In addition, it is mobile operators who can find out about traffic jams faster than traffic police officers.

But you need to understand that statistical information is very willingly purchased by financial institutions, developers and various retail chains. This is why we often encounter spam mailings and calls.

Information received by intelligence agencies helps prevent terrorist attacks. However, for many people, interference in their personal lives is not only unpleasant, but also unacceptable.

( 1 rating, average 4 out of 5 )

How many contacts fit on a SIM card

Having figured out what types of SIM cards exist, you need to answer the main question: “How many numbers fit on a SIM card?” It was previously noted that SIM cards differ only in size. But some operators impose peculiar restrictions on chips. They relate to the available memory capacity.

For example, an MTS SIM card can hold 250 numbers. Owners of Megafon SIM cards can add 200 contacts to their phone book. But Tele2 manages to retain only 100 subscribers. Business people will definitely not have enough of a notebook that can hold 100 numbers. We need to look for a way to increase storage.

How to expand your phone book

If your SIM card runs out of space for storing contacts, there is no need to be upset. There is an ideal way out of the situation, allowing you to increase your starting storage from 250 to an almost infinite number of numbers. All you need to do is save the numbers not to the SIM card, but to the phone’s memory. A similar option is offered whenever the user is about to add a new subscriber.

If the number is already saved in the SIM card’s memory, you can copy or move it to your phone. To do this, you will need a standard phone book application, in which you highlight the desired contact, and then press the “Copy” or “Move” button.

Another way to place more contacts than necessary is to use any messenger. Now there are a huge number of them: WhatsApp, Viber, Telegram and others. Calling applications have their own phone book, which does not take into account the number of numbers stored on the SIM card or smartphone.

Even when all the numbers are saved in the memory of the phone or instant messenger, there is still a risk of losing them along with the device. To prevent this from happening, it is recommended to constantly update the backup copy of the data on your smartphone, sending the backup to the cloud. There, numbers and multimedia files will be stored exactly until the user wants to restore the copy.

SIM card memory

When using a physical SIM card, the subscriber has access to the internal memory in its chip. Just like any phone, it has a storage device installed on which the operator writes his identifiers and additional software, and the free part of the memory remains available to the user.

The memory capacity of SIM cards is not large, although in the latest generation it is twice as much as was previously available. However, despite the increase in memory, the possibilities for the user did not become greater, and sometimes were reduced.

Before the mass distribution of smartphones and cloud accounts to store their data, many used SIM card memory to store contacts and SMS. Note that now the maximum possible number of such records is about two hundred and fifty.

But it all depends on which SIM card is used by the subscriber. Operators use SIM card memory not only to record technical data for identification, but also their application. It allows the subscriber to receive various information and additional services, including mainly content ones.

You can also store messages on a SIM card, but the restrictions on them are much more stringent. On average, a SIM card can store up to thirty SMS messages. And here it is worth considering that, unlike the memory of the phone itself, each message is stored separately, and the volume in Latin does not exceed 140 characters. Therefore, if a larger message has arrived, then it will be stored on the SIM card as two, three, or more separate SMS. Also, only incoming text messages are saved on the SIM card.

Note that the memory capabilities of SIM cards are not fully used, which can explain the lack of interest of modern users. Now a SIM card has the ability to store more than one number for each contact, and there may also be a larger limit on the number of characters in the name.

How to properly store contacts on your phone so as not to lose them at the most important moment

The list of contacts in modern smartphones can be stored in three places at once: in the phone’s memory, on the SIM card and in cloud services. Let's figure out where it's best to do this, so that at the most important moment you won't be left without critical information.

The simplest and most common way to store contacts is on the phone itself. As a rule, any modern device has an impressive amount of memory, which can easily accommodate thousands of contacts. What’s important is that when you save a number in your phone, you can specify a bunch of related information along with it: home phone number, email, subscriber address, etc.

Unfortunately, storing contacts in the phone's memory has one fundamental drawback. If the gadget suddenly breaks or is reset to factory settings, then along with all other files you will lose your contacts. Hundreds of numbers will have to be re-recognized and entered again.

Where to store contacts

Which way to ultimately trust your contacts? Let's explain. None of them will give a 100% guarantee of the safety of your numbers, but a combination of all methods at once is quite possible. We save all the numbers in the phone’s memory, set up their duplication in cloud storage, and also add the most important contacts to the SIM card. After this, the chance of losing your numbers in a critical situation tends to zero.

On topic: The most important SIM card setting that everyone forgot about

SIM card

Each SIM card has a small amount of built-in memory - it’s too small to store files there, but for several dozen or even hundreds of contacts it’s fine. The advantages of storing contacts in a SIM card are obvious - problems with the phone will not affect the SIM card, so nothing will happen to the numbers even if the gadget breaks down. It is enough to move the SIM card into a new phone so that the usual list of contacts is at hand.

The key problem with this storage method is that only a few numbers can fit on a SIM card. Moreover, SIM cards differ in memory capacity from different mobile operators. So, old SIM cards from MTS can store up to 250 contacts, new ones can store up to 200, SIM cards from Beeline and MegaFon can hold 200, and Tele2 can only hold 100 numbers.

Poking around in the SIM card: processor, memory, file system + I/O

It is difficult to find a person who does not know what a SIM card or Subscriber Identity Module is. This piece of plastic with gold contacts on one of the surfaces is the key to the services provided by the mobile operator. And inside the SIM card there is a specialized computer with quite complex functionality.

A SIM card is the same processor credit card, but with a profile

A SIM card is actually one of the varieties of a more general entity - a processor “smart card” (Smart Card).

Processor in the body of the SIM card
Such “smart cards” can be used for various purposes:

Identification of mobile subscribers.
Providing access to encrypted content of various paid systems, for example, television.
Like bank cards
To identify a user who is granted access to corporate networks, etc.

In different mobile communication systems, subscriber identification modules are called differently.
The GSM standards used the name SIM - Subscriber Identity Module, which became firmly established in everyday life. The identification module used in UMTS (3G) networks is often called USIM - Universal Subscriber Identity Module, which is actually not entirely true! The module itself is called UICC - Universal Integrated Circuit Card - a universal card with an integrated circuit (“smart card”), and USIM is an application that runs inside the UICC and is used to identify and service a subscriber in the UMTS network (3GPP TR 21.905) . In CDMA networks, R-UIM - Removable User Identity Module is used to identify subscribers. The word Removable (removable) emphasizes its new status, since previously, in IS-95 networks (the communication standard on the basis of which CDMA networks operated in the USA, Russia and other countries, for example, SONET in Moscow), elements identifying the subscriber were placed among electronic phone components. Obviously, using R-UIM greatly simplifies replacing a phone when it malfunctions or buying a new one, and allows you to use a phone of a different standard in roaming.

But further we will talk about subscriber identification modules used in GSM-UMTS networks, which by tradition we will call SIM or cards.

Let's compare cards?

Currently, three formats of GSM-UMTS subscriber identification modules have been standardized.

Three formats of GSM-UMTS subscriber identification modules

ID-1 UICC - the very first option - is the size of a regular bank card. Many people remember it from the models of the 90s - Motorola 8900, StarTAC and others. Currently, it is practically not used in new models of mobile terminals due to its large dimensions.

Plug-in UICC is the most common format today. Typically, such modules are broken out of ID-1 size cards using notches made during manufacturing.

Mini-UICC is a card format that Apple began using in the iPhone 4, iPad, iPad 2. Now other manufacturers of mobile phones and other devices intend to produce models into which modules of this particular format will need to be inserted. This format is sometimes called 3FF, or colloquially “micro-SIM”. And these cards are usually broken out of an ID-1 format card. The reasons for the appearance of such diversity are obvious - saving space inside the phone body.

They try not to do a universal notch, which allows the user to break out a module of both Plug-in and Mini-UICC sizes from the plastic of an ID-1 card, at the user’s choice, for reasons of reliability - when trying to break out a card for the Plug-in format, it is very easy to damage the remaining thin jumpers, after which the Plug-in card will not stay securely in the phone.

ID-1 card with “universal” notch for Plug-in and Mini-UICC

And the displacement of the SIM card in the holder threatens problems with the operation of the phone. Minimal trouble - the phone simply does not sense the presence of the SIM and does not register on the network. In the worst case scenario, it can turn out like when the wires are mixed up - voltage gets to the wrong address and a short circuit with unpredictable consequences.

Manufacturers of mobile terminals, some actively or less strongly, usually object to the use of adapters that are advertised for the use of Mini-UICC format cards in phones designed for Plug-in format cards. The adapter is slightly thicker than the Plug-in module, and in addition, the slots at the junction of the card and adapter can break the contacts in the phone when installing a SIM, depriving the user of a chance for warranty repairs.

In some devices operating in the mobile network (navigators, devices for monitoring the location of vehicles, etc.), subscriber identification modules can simply be soldered in the form of microcircuits, but ordinary subscribers usually do not have to deal with such modules.

How many contacts should there be?

In everyday life, there are modules with different contact pad designs and different numbers of contacts.
Some drawing of a contact pad as your business card. The standards provide 8 positions for sites through which modules are connected to mobile terminals, but not all of them are always used. Often there are cards with 6 pins, and the rest of the metalized part is usually connected to ground.

Cards with 6 and 8 contacts

Contacts used: C1

— Vcc — power supply;
C2
- Reset - card control contact;
C3
- CLK - Clock - clock frequency;
C5
- general (“ground”);
C6
- Vpp - programming voltage, which is used when recording service information
C7
- I/O - serial input/output interface line.

The standards provide for the use of both contacts C4 and C8 in the mode of exchanging information with a mobile terminal in USB mode, which provides a higher information transfer speed than through the usual I/O SIM interface.

In practice, the USB interface mode is not actually used now, since equipment with this interface is practically not produced or ordered by consumers, so these contacts, even if they are on the card, are connected to ground. In the future, work through the I/O interface line will be discussed.

Where did they plug the computer?

Comparing the electronic contents of a SIM with a computer (especially a pocket one), you can find many elements that are identical in function:

Processor (CPU);
Random access memory (RAM, RAM);
Read-only memory for storing the operating system ROM (ROM);
Memory for storing user information;
File system;
I/O controller.

There are also differences - things that are not in the module:

Elements of the human interface that are simply not needed by the module.
Power supply (uses terminal power)
Clock frequency generator (similarly, supply from the terminal).

Additional information about the architecture and production of SIM can be found in this topic.
The amount of memory that can be used to store information in a SIM varies and is gradually increasing as technology develops. A few years ago there was an outburst of euphoria from the advent of technology that made it possible to store gigabytes of information in a SIM. It was then, after a heated discussion in the industry and two rounds of voting in the GSM Association, that the USB standard was chosen for working with large amounts of information. But then the euphoria subsided, and now there are not many mobile terminals on the market that can work with such SIMs, and SIMs with gigabyte memory are not in particular demand among operators.

Can HD movies be stored on SIM cards?

Why do we need large amounts of SIM card memory and what amounts of memory are really needed? SIM memory is used for several purposes:

Storing information that is vital for the phone
with this SIM to operate in the mobile network. For example, this is IMSI - International Mobile Subscriber Identity - a sequence of numbers that not only identifies a specific SIM and its owner, but also indicates which operator from which country issued it. This information helps in roaming to quickly figure out where to find out what services can be provided to the phone with this card, because the first three digits of the IMSI are the country code, and the next two digits are the network code (in the Americas, the network code consists of three digits). This is Ki - a secret key that allows the network to make sure that this is really “its” SIM card, and not some fraudster using someone else’s IMSI to gain access to services. Plus files for storing other service information.
Storing user information
. Usually the cards contain a phone book and received SMS messages. In cards for the UMTS network, the phone book can have much more functionality than just a list of names and their corresponding phone numbers. You can attach several numbers to a name, add an email address and other information. However, due to the development of these same functions in the phones themselves, these SIM capabilities are practically not used.
Hosting application files
that can run in the SIM's built-in Java virtual machine and provide some services. If the operator actively uses services based on applications running in the SIM card, then this part may occupy the most significant part of the card's memory.

It is also obvious that increasing the amount of memory increases the cost of SIM, and therefore now operators, most often, try to limit themselves to the minimum volumes necessary to accommodate the necessary information.

Who rules whom?

In addition to the fact that the phone or other mobile terminal provides the SIM card with power and a clock signal, it is also fully responsible for the exchange of information between devices - the phone always acts as a master, and the card is always a slave.
The phone sends commands/requests to the SIM, and the SIM only responds to them, accompanying the responses with information about the response status.

In the status information, the card can confirm that the command was successful, ask for additional time to prepare a response, report errors of various types, or indicate that it has special information for the phone, which it can obtain by sending a special fetch request in the next command .

This mechanism for transferring information from the card to the phone is usually called the SIM (or Card) Application Toolkit, STK. It is used to implement various services based on application programs (usually written in JavaCE - Java Card Edition) running inside the SIM. In the menu of phones with installed SIM cards of the main operators, you can find items and entire menu trees formed on the basis of information provided by applications running in SIM cards.

The operation of real-time services is based on the same technology, for example, constantly providing information about the current balance.

It is possible to organize roaming for small companies by switching two IMSIs in one card - one corresponding to its network, and the other provided “on loan” by another operator - the “big brother”. For example, Beeline networks operating in the CIS countries use the Dual IMSI mechanism to provide roaming services to their subscribers. Their SIM cards contain one IMSI of their network, and another IMSI corresponding to the Russian Beeline network. In the Russian Beeline network, these IMSIs are reserved in HLR for provision to companies and communication channels with them are organized. A Beeline subscriber from a “subsidiary” company, being, for example, in a European country, uses the STK menu to switch the SIM operating mode to roaming. As a result, a phone with such a SIM card appears to the roaming network as belonging to a subscriber of the Russian Beeline network. Then everything happens as usual, only the Russian Beeline network organizes the transfer of information on behalf of the “daughter” network.

You can even organize a WEB server inside SIM! So, if someone is embarrassed by the “slave position” of SIM, he may well consider it a server.

How does it turn on and why does it load the book slowly?

After turning on and starting the operating system, the phone supplies the SIM with supply voltage Vcc.
The standards provide for three SIM supply voltage ratings – 5V, 3V and 1.8V. Previously, cards were produced that could only operate at 5V. After the advent of phones that supplied a voltage of no more than 3V to the card, these old SIMs were gradually replaced by new ones capable of operating on 3V, which can also withstand operation in phones providing 5V. Since there have not yet been any phones that provide SIM cards with only 1.8V voltage, modern SIM cards do not create compatibility problems due to supply voltages.

After the phone is supplied with power, a clock signal is sent, and after establishing a stable mode, the voltage at the Reset contact rises. This serves as a signal for the SIM card to start working with it, to which it responds with a sequence of bytes called ATR (Answer To Reset).

ATR bytes contain basic information about the card's capabilities and supported communication protocols. In particular, it can tell the phone possible options for speeding up the exchange of information through the interface by increasing the clock frequency and information transfer speed.

After reading the information from the ATR, the phone can launch the PPS (Protocol and Parameter Selection) procedure to coordinate the mode of information exchange between the phone and the card. If the phone is unable to find an option that is acceptable for both it and the SIM, then communication with the card will continue in the default mode (at a speed of 9600 bps).

In such cases, subscribers often complain that it takes too long to read the phone book from the SIM card into the phone, for some reason reproaching the operator who issued the SIM card.

"Hello, who are you?"

During the switching process, the SIM card and the mobile terminal (phone) exchange “business cards”. The phone reads a file from the SIM containing SST - SIM Service Table - information encoded in a certain way about those STK functions that the SIM can perform. In turn, the phone sends TERMINAL PROFILE to the SIM card—certainly encoded information about what functions of communication with the SIM it can support. As a result, both parties receive information about the partner's capabilities and can interact correctly when implementing STK-based services.

File system and security

SIM has a multi-level hierarchical file structure with access control.
Access to files is regulated by the need for the user to provide various types of access codes in advance. Some of these access codes are well known - these are Personal Identification Numbers - PIN (aka PIN1) and PIN2. Other codes are used for administrative access to service files.

What does such a distinction provide? An activated PIN request allows you to protect the money in the personal account associated with the SIM card from unauthorized use by unauthorized persons.

Another important security technique is, for example, the impossibility of reading information from some files, for example, reading the Ki key, which is used in various cryptographic algorithms for subscriber authentication and the generation of traffic encryption keys.

Why is it useful to read instructions?

Several years ago, at a round table on the prospects of smartphones, organized by one of the manufacturers, one of the participants complained to me that Beeline lacked a service that was very useful for parents.
He wanted parents to be able to limit their children’s ability to call only a certain set of phone numbers - home, parents, grandparents, and the child’s phone should not call other numbers. Imagine his surprise when I showed him the operation of the FDN - Fixed Dialing Numbers function, which is implemented by the joint actions of the phone and SIM card. Allowed numbers using the phone are simply written to a specific SIM card file, and access to change this list is blocked using PIN2. After this, a phone with such a SIM will refuse to call numbers not listed in the FDN list.

However, it should be noted that not all phones support this service.

Wash your hands before eating

The skin of the fingers is covered with organic fatty acids, which upon contact cause corrosion of metal parts. Small details are just about the SIM card contacts. The photo shows a laser pointer, the surface of which, after quite rare use, has lost several layers of metal coating - chrome plating and copper plating precisely because of these fatty acids! As you know, “radio engineering is the science of contacts,” and SIM has a lot of them!

Laser pointer affected by fatty acids on fingers

A similar fate should not befall the SIM card contacts, and to do this, you need to protect the SIM contacts from contamination by all means, and try not to touch them with your fingers!

If there is a problem with the contacts between the phone and the SIM, then carefully cleaning the contacts with a soft eraser can help. Just don’t remove crumbs from the contacts with your fingers after the cleaning operation, otherwise all the problems will start all over again! It’s better to just blow them off or carefully wash them off with alcohol.

To change or not to change?

One day, a subscriber came to the Beeline office and was sent from a phone repair service to change his SIM card because his brand new phone turned off spontaneously during a call, checking his balance, or sending an SMS.
I had to explain to him that turning off the phone has nothing to do with the serviceability of the SIM. Using an eraser, I carefully cleaned the contacts on the battery and the phone, after which the phone began to work normally. Along the way, I gave the subscriber a short lecture on hygiene.

Of course, the situation is not so obvious in all cases, and it is not easy to determine who is to blame - the phone or the SIM for the fact that the services do not work - after all, their communication takes place almost intimately. It is especially important to understand the causes of conflicts when developing new services that use STK or when problems of SIM incompatibility with certain models of phones or other mobile terminals are discovered.

In such cases, an information exchange protocol analyzer on the SIM-terminal interface provides an invaluable service:

Analyzer of information exchange protocols between SIM and mobile terminal.

Instead of a SIM card, a special probe is inserted into the terminal, and the SIM is connected via a flexible cable. During operation, all information about events occurring on the interface is recorded in the memory of the computer connected to the analyzer.

Comparing the collected information with the requirements of the standards allows us to unambiguously and convincingly identify the party at fault in the conflict.

Of course, the material touches on only some of the features of SIM cards and how they work in phones, but if you are interested in this topic, just ask questions, I will answer in detail.

PS Today Boomboorum wrote another review of our office.

Cloud storage

The most current way to store contacts is cloud services. They allow you to insure yourself in case of problems with your phone or loss of your SIM card. By default, this function is implemented both by Apple, where the numbers stored in the phone’s memory are automatically duplicated to the iCloud cloud, and by Adroid, where the numbers are linked to your email. The method is as convenient as possible, since even when purchasing a new smartphone, there is no need to enter contacts again - the old ones will be transferred to the device from the cloud.