A Subscriber Identification Module card, better known as SIM card is chip found in cell phone and it is a small memory card which is removable and stores data. SIM card is made up of electronic parts and plastic. It works on native card or java card operating system.
History of SIM card
SIM cards were first found by german company, Giescki, Devrient in 1991.In first generation the size of SIM cards were like credit cards. Later the phone manufacturers produced smaller phone which can be held in hand, due to this SIM card manufacturers made them smaller. The diameter of SIM card manufactured now is in centimeters.
According to experts at Pro Phone Repairs of Albuquerque, the dimension of SIM card is 15mm x 12mm size and 0.76mm of thickness. Nowadays corner of SIM card is cut with an angle, to make the user to insert the card correctly in its cradle. It stores more amounts of data and it behaves like mini hard disk.
Uses of SIM card
- SIM card like the M2M SIM card is capable of storing phone numbers, text messages and contact names. Phone number is assigned for SIM card, which makes the receiver to identify the caller based on phone number from which we dial. Each SIM card has printed information. The information is known as international mobile subscriber identity (IMSI).It has numbers in series. The three numbers at first are represent the country code of mobile. The next two digits is mobile network code. The following last ten digits represent mobile station identification.
- It is easy to transfer SIM card from one phone to another without re-keying all the data. If the user buy new mobile, then the SIM card can be removed from old phone and can be fixed in new phone. This is convenient for those people who upgrades or changes the phone.
- SIM cards are network locked, which means the service provider and phone number cannot be changed when we change the phone. So, the SIM card won’t work when we use different phone network. There are phones which are SIM locked i.e. it will work only for network from which the phone is bought. This situation occurs when phone is sold for contract under carrier. The network provider gives free phone in exchange of one year service commitment from user.
- If long term commitment of service is not required then the user can buy a pre-paid SIM card. Certain amount has to paid for amount of text credits or talk time minutes. When it gets over, add load by buying.
- SIM card in the phone can be found by removing the protective cover which is backside of phone unit. The SIM card lies below battery, so the battery has to be taken out. The SIM can be pulled out or slided up as they are inserted between metal clips. SIM card is a memory device in a phone.
