A SIM card is short for Subscriber Identity Module card. It is a tiny encoded circuit board which is fitted into GSM cell phones at the time of signing on as a subscriber. It holds the details of the subscriber, security data, and memory to store personal numbers. A SIM card can stores any type of information Which helps the network service provider to recognize the caller.
A SIM card is a removable memory card and can be put into any compatible GSM handset, permitting the user to keep the same number while changing handsets. It is a standard unique chip which is a must in every GSM cell phone.
The working of a SIM card
A SIM card works as a digital brain of a cell phone. The validation and encoding ability of a SIM help to stop your cell phone from being stolen and your conversations from being overheard. The SIM card can store personal data, user ID and billing information and can be interchanged between phones. So you can easily receive personal calls even while using someone else phone just by installing your unique SIM in that cell phone.
Some cellular phone carriers cell phones in a locked condition. If you have such a cell phone, then in that case you can’t able to use different SIM cards without unlock your phone.
If you have a country specific SIM card, then you can use only in that country, you can’t use that SIM card in different country. A U.S. specific SIM card may give you limited coverage while traveling through Europe or some of the Greek Isles. Most country specific SIM cards have voice mail so a caller can leave you a message if your cell phone is turned off or not reachable.
SIMKey Keyring Databank
Ever misplaced your cell phone or had it stolen? Well, in that case buying a new cell is bad enough, you have to re-enter all you contacts in your new SIM card, its very difficult task to do. A SIMKey Keyring Databank is a novel device which helps you to backup your SIM data so that you never have to worry about losing vital information. You simply put your SIM card into this device, follow the simple directions and have a backup SIM card ready.
SIM cards are used with carriers that operate on the Global System for Mobile Communication (GSM) network. The competing network is Code Division Multiple Access (CDMA), a technology created by U.S. company Qualcomm. As of fall 2005, CDMA cell phones and CDMA carriers do not support SIM cards in most parts of the world, though this is changing. A CDMA SIM card called the R-UIM (Re-Useable Identification Module) was made available in China in 2002, and will eventually be available worldwide. Expectations for the future include a cell phone market that supports both SIM (GSM) and R-UIM (CDMA) cards by default.