What is the full form of SIM:

SIM represents Subscriber Identity Module.

It is an IC chip which safely stores the details which are important in mobile communication. It stores International mobile subscriber identity number (IMSI) and its key. This key is used to identify and authenticate the subscribers telephonic details.

SIM is a kind of a card which is placed inside mobile telephones which provides different facilities to the users. It provides a unique number which is used to setup a network between the operator and the mobile user. SIM cards can be transferred between different mobile devices. They can store contact numbers and messages. All the GSM phones use SIM cards.

Old SIM cards could store a very limited data. But the modern SIM cards can store almost 250 contact numbers. The data storage capacity of the SIM cards has been increased. Also the data from the SIM can be copied to the handset, without discarding the details present in the SIM card. Initially, SIM cards where as big as credit cards or debit cards provided by the banks. But gradually, the size of SIM cards has reduced, whereas the functions have remained the same, and some are upgraded. In recent past, full size SIMs were reduced in size and mini SIMs, micro SIMs, and nano SIMs have been introduced.

The SIMs launched before the year 1998 use 5 Volts, whereas the modern SIMs uses 5V, 3V and 1.8V. New SIM cards help to upload applications which the user wants to subscribe.

SIM cards store the information related to the network provider. It stores the Location Area Identity. Each network operator has a unique Location Area Identity number. Whenever the mobile devices moves from one place to another, the location area gets changed, and the SIM updates the new LAI number. It removes the previous LAI number and data related to that LAI, and stores the new LAI number with its data.

Questionnaire:

Q. What is the full form of SIM?

A. Full form of SIM in English is Subscriber Identity Module or Subscriber Identification Module.

Q. What does a SIM represents?

A. A SIM represents a way to provide a unique identity to every mobile user. It provides a unique ID number to every user and keeps the user in touch with the network operator.

Q. What are the uses of SIM?

A. SIM is used for keeping the user in touch with the network operator. It stores the IMSI number which is a unique number. It can be used to store the contact numbers and messages.