What is a SIM card?
The SIM card is basically the “brain” of the phone. It contains all the information your phone requires to connect to a phone carrier in order make and receive calls. Without a SIM card, your GSM phone is useless. The SIM card in your North American cell phone is programmed to charge international long distance and roaming rates when you travel outside of North America. Roadpost SIM cards save you money on costly fees from your domestic carrier and work easily in any unlocked GSM phone.
A SIM card is a small chip that contains information about your phone service, such as your phone number, user ID, billing information and rate plan, and authorizes you to make calls on a network. All GSM (Global System for Mobile Communications) handsets require a SIM card – your handset’s interchangeable memory. This means you can make and receive calls on any unlocked handset to your SIM card’s telephone number. Changing or upgrading your handset is as easy as inserting your SIM card into your new phone.
: A SIM card is a specially programmed microchip that inserts into a Global System for Mobile Communications (GSM)-compatible mobile device. The SIM card encrypts transmissions and identifies the user to the mobile network. Without a SIM card inserted into the mobile equipment only emergency calls to 911 can be made. SIM cards allow users to easily switch their account information between other compatible GSM devices for immediate use. SIM cards also act as a removable storage device within the mobile equipment. SIM cards contain up to 128 KB of available memory for storing contact names and phone numbers as well as text messages. This allows for users to easily update their new mobile device with the phone book. You can learn more about using your SIM card by visiting Phone & Device Tutorials. Other topics of interest: How do I install my SIM card for my wireless device? What should I do if my SIM is blocked?
The SIM (Subscriber Information Module) card – a.k.a. “smart card” – holds all of a subscriber’s personal information and phone settings. In essence, it is the subscriber’s authorization to use the network. It also holds the phone number, personal security key and other data necessary for the handset to function. The card can be switched from phone to phone, letting the new phone receive all calls to the subscriber’s number. Back to the top How do SIM cards work? The SIM is inside each handset and functions as its digital brain. The authentication and encryption capabilities of the SIM prevent your phone from being stolen and your calls from being eavesdropped on. The SIM’s digital memory, which stores information like your rate plan, phone number and service features, also allows you to easily personalize your service and contains user ID and billing information that can be switched between different phones. So, with your SIM card installed, you can make or receive calls personally ev
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.
