SIM cards are essential to our phones. But, this element has changed a lot in a few years. Its size has considerably reduced, while its memory has increased. A quick reminder about this electronic component
There are now more SIM cards in circulation than inhabitants in France (77 million) or in the world (20 billion) in 2020. The recent arrival of eSIMs should further boost the SIM card market, especially with the development of the Internet of Things (ioT). Currently more than 1.2 billion eSIMs are in use worldwide, but Juniper Research predicts that this number will triple by 2025.
What is a sim card used for?
A SIM card, whatever its format, is essential to use a phone or rather to have access to a cell phone network. Its name stands for Subscriber Identity Module. The SIM card has several functions. First, it uniquely and securely identifies a user (the famous PIN code). Secondly, it is small and removable so that it can be transferred to another phone. Thirdly, it embeds a storage space (the memory) shared between the user (contacts directory, possibly app settings) and the phone operator (connection settings, messaging settings, contract options). In other words, the SIM card is the key to unlocking a cell phone, but also a mini safe.
What is a sim card?
A SIM card is an electronic chip containing a microcontroller (a very basic kind of processor) and a memory. To communicate with the cell phone, the SIM has contact areas. On the old mini SIM cards, there are only 6 contacts. On recent mini/micro/nano SIMs, there are 8 contacts to exploit new functions and add support for faster transfer via USB. There is no standard on the power supply voltage of SIM cards. Some SIMs require only 1.8V while others require 5.5V. The memory of the first SIM cards varied between 2 and 32 Kb. It has evolved between 32 and 256 KB with micro SIM.
If the first SIM cards were produced by the German company Giesecke & Devrient for the first mobile network Radiolinja (in Finland), they are derived from the smart card. However, the smart card is the work of the Frenchman Roland Moreno. More precisely, he was the first to file and perfect patents and certificates on the modern smart card. In 1947, a British engineer was already working on a portable electronic memory. Germans from the company Giesecke & Devrient, and later Americans improved this electronic storage.
The different types of sim cards
There are 4 types of physical cards and one type of virtual card (eSIM). Miniaturization has made it possible to reduce the size of phones and / or to give more space to other electronic components such as the camera or battery.
1- The SIM card
The “classic” SIM card looks like a bank card (85.6mm long, 54mm wide and 0.76mm thick), but does not use the same protocols. It was the first format to be used in the early 90’s, but it was quickly abandoned as too bulky. Its technical name is 1FF (1st Form Factor) or ID-1 (ISO/IEC 7810) according to the International Organization for Standardization of Identification Cards.
2- The mini SIM
The mini SIM is abusively called standard SIM card and appears in 1996. This format (25 mm long, 12 mm wide and 0.76 mm thick) is still the most common, but tends to disappear with the arrival of smartphones and the renewal of phones. Its technical name is 2FF format or ID-1/000 defined by ISO/IEC 7810.
3- The micro SIM
The micro SIM arrived on the market in 2006 with the LG U900, but it was popularized by the iPhone 4 in 2010. Its specifications were set in 2000 by the ETSI (European Telecommunications Standards Institute) under the reference ETSI TS 102 221 V9.0.0 Mini-UICC and has a format 3FF (25 mm long, 15 mm wide and 0.76 mm thick). Apart from its size, it offers the same layout of electrical contacts and the same thickness. It can therefore work on older phones with an adapter.
4- The nano SIM
The nano SIM (4FF) is the smallest physical SIM card (12.3 mm long, 8.8 mm wide and 0.67 mm thick). It appears with the iPhone 5 in 2012. It has a surface area reduced by 30% compared to the micro SIM. The number of electrical contacts and their arrangement are the same as on previous SIM cards, hence a backward compatibility.
5- eSIM: the virtual SIM card
The eSIM is currently the latest generation of SIM. It is the dream of phone manufacturers, a SIM linked to the phone. The eSIM (emboarding SIM) is as its name suggests integrated into the phone and takes up even less space than a nano SIM. It is an electronic chip that is immovable. Apple is the first to equip its iPhone with eSIM on the iPhone XS and iPhone XS Max. It is also found on several connected watches like the Apple Watch Series 5 or the Samsung Galaxy Active 2. The latest iPhone 13 and 13 Pro even have dual eSIM.
What are the advantages and disadvantages of esim?
As the eSIM is integrated in some phones, the use of a cell phone is generally possible in less than an hour while via an order on the internet, you have to wait for the physical card in your mailbox (48h minimum). With the eSIM, there is no need to go to the operator’s store. Moreover, the eSIM avoids rare problems of malfunctioning of a classic SIM card. The eSIM allows the change of phones, without worrying about its format (provided you have a compatible phone). Finally, eSIM is usually offered on phones in addition to a SIM card slot.
In other words, you can have two phone numbers on the same phone. In addition, if you often travel abroad, you can keep your French phone number while taking a local and cheaper subscription to call in your country of stay. An eSIM accepts up to 5 different profiles on a phone.
On the other hand, the eSIM is an electronic chip welded to the phone. If your phone is out of battery or damaged (water immersion, broken screen…), you can not remove the SIM card to use it on another mobile. In addition, eSIM does not offer phonebook storage. This will be kept on the internal memory of the phone
For the moment most European operators refuse to grant eSIM profiles to mobile virtual operators. The exception is Prixtel (Orange network) and Ubigi (via Transatel) in France.
Can i use a sim card on a phone that accepts another format?
When subscribing to a new service, the phone operator usually sends a SIM card in double or triple cut. On a triple cut card, you get a bank card format (1FF) with a pre-cut miniSIM incorporating a pre-cut microSIM itself incorporating a pre-cut nanoSIM. On a double cut card, you just get a miniSIM with a pre-cut nanoSIM. Do not throw this card away, as it usually contains the PUK code and provides an adapter.
- If you want to switch from a mini SIM card to a micro/nano SIM or from a micro SIM to a nano SIM, it is possible to cut it manually.
- If the SIM card slot of your phone is too big for your SIM card, then you have a nano SIM or micro SIM. There are commercial adapters to convert small SIM cards into larger ones.
Why doesn’t my new sim card work on my old phone, despite the adapter?
SIM cards have evolved a lot in 30 years, not only in their format, but also in their technology. There are two common types of incompatibilities.
- On the one hand, it may be a problem of contacts. No, it’s not your telecom connections or your phone book. Contacts are the metal areas (usually gold for better conductivity) on a SIM card. At first it had only 6 and now it has 8, so if your mobile is old, its pins will come into contact with the wrong areas of the SIM card.
- On the other hand, it may be a voltage problem. Originally, SIM cards required a voltage of 3V. As SIMs have become more sophisticated, the voltage has increased to 5 or 5.5 V. The old SIM cards have a protection against overvoltage and are therefore inoperable on recent mobiles.
How to use my esim on my compatible phone ?
The US cell phone operators have made things simple. Whether you are a AT&T, T-Mobile, U.S. Cellular or Verizon, the procedure is the same as with a physical SIM card. When you subscribe to a package (or buy a prepaid card), you have the choice between ordering a physical card (the famous SIM card with triple cut) or an eSIM. You activate the option on your account.
The operation is charged as with a conventional SIM card, but unlike the latter the activation of the line will only take a few hours instead of days. On your customer area, you just have to scan a single-use QRcode and that’s it. Be careful when you change your phone, as the phone subscription is linked to the phone until you deactivate it. As with a traditional SIM card, the PUK code is indicated at the time of subscription and available in your customer area.
How to unlock a phone?
Operators offer to lock the phones sold in their stores to work only on the network of a particular operator. In return the cost of acquisition is lower. This is the SIMlock.
I entered a wrong pin code several times, my sim card is blocked, what to do?
You need the PUK code (PIN Unlocking Key) to unlock your SIM card. It is normally found on the double or triple cut card accompanying your subscription. If not, you can retrieve it from your customer area on the internet or your mobile app.