What is the full form of SIM?

The full form of SIM is Subscriber Identity Module, also known as the Subscriber Identification Module. International Mobile Subscriber Identity (IMSI) is stored on a portable chip with a built-in circuit known as SIM. It is a smart memory card that enables us to make a phone call anywhere in the world while maintaining the user’s constant contact network.

On GSM networks that are operated and controlled by smartphones, SIM is typically used. It can be used with any mobile device that supports this and is portable.

Devrient and Giesecke, a smart-card manufacturer, based in Munich, created the first SIM card in 1991. The European Telecommunication Standards Institute was the organisation that first acknowledged and declared the SIM.

The SIM card houses a lot of information, transfers important data back and forth to the users’ network, and contains some of their private and personal information. The list of data that SIM stores are:

• Address details
• Text messages
• Personal security keys
• Phone number
• Data regarding network authorization.
• Other data.

A few crucial data carried out by SIM are listed below:

• IMSI (International Mobile Subscriber Identity)
• Unique serial number
• Security information
• Brief details related to the local network.

When SIM was first manufactured, it was almost the size of a credit card. However, the later size of the SIM, which was eventually made public, had a capacity of 15 mm by 12 mm. The nano and micro SIM chip sizes are now used in some smartphones.