TechTelecom Dictionary

What is the hardware structure of SIM card?

SIM card stands for Subscriber Identity Module. It is a piece of hardware with Integrated Circuit inbuilt within, acts as a bridge to communicate between mobile phones with mobile network(telecom operator).

Each SIM card is so unique that it contains unique identification number along with various details of the users. The details like the network operator code, personal user key(PUK), security code and algorithms are stored inside the SIM card. Each operator have its own SIM card. So using the one operator allows the user latch within their own network only.

With so much small size, SIM generally contain 64KB memory. It can store 250 contacts and around 52 messages. Not only this, SIM card by default contains the network operator and user information stored within it. Such information is not accessible to the user but can be accessed by the telecom operator.

Now lets discuss the various elements of the SIM card:

hardware structure of SIM card
Fig: hardware structure of SIM card

The picture above is the 6 pin SIM card. There is 8 pin SIM card also. The different types of SIM card is discussed here. But now lets discussed the 6 Pin SIM card hardware structure:

1. Vcc: It is the supply voltage pin of the SIM. It supports the 5V DC power. To operate the SIM card, this Vcc pin must be supplied with 5V DC then only the IC(Integrated Circuit) embedded within the SIM card will work.

2. RESET: It is the pin used to reset the SIM card signal and communications. Upon using this pin will make the SIM in default mode resetting all the current signals. The RESET pin is activated by the mobile devices or the SIM card upon required. Generally, SIM users are given less permission to use this function.

3. Clock: It provides the SIM with a clock signal for its processor. The clock is derived or inherited from the mobile or the hardware.

4. GND/Ground: It is the common reference voltage. Normally we called ground as the low voltage point. As SIM is a small electronic hardware with Integrated Circuit, it also have the common reference point and hence this pin is named as the ground. GND now complete the circuit for the proper functioning of the SIM card.

5. Vpp: Earlier, this pin is used to carry the extra voltage required to write or erase the data in the memory of the SIM card but now it is not quite useful as this work is done by the Vcc.

6. Input/Output: It is used to read and write the data in the SIM card from the mobile phones. It is half duplex communication pin acting as a data transfer pin.

As the SIM card is getting smaller and smaller, the performance and capacity is increasing day by day and its all thanks to the new technology and research.

What do you think the new SIM card will be like? Let us hear in the comment section below.

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