By: Christine Martz
Meaning of SIM – “Subscriber Information Module”, is a programmable card that
stores all of a cell phone subscriber's personal information and phone settings.
It is otherwise known as a "smart card". The SIM card is used by the subscriber
as an authorization to use the network. The card stores the phone number, personal
security key and other data necessary for a phone's functionality. A subscriber
can switch the card from phone to phone which makes the new phone receive all
calls to the subscriber's phone number.
A SIM card is one type of a security device that is used
on GSM networks. It makes stealing numbers or making fraudulent calls difficult.
The card also makes it possible to roam within other GSM operators around the
world when the SIM card is transferred to a phone that uses the correct frequency
band for the countries being traveled to.
“…GSM phones have SIM (Subscriber Information Module) cards inside.
Without a SIM card, a GSM phone is just a paperweight. It has no information about the
carrier, your plan, or any of the other things it needs to join the network. The nice
thing is, if you can get your phone unlocked, you can go to many other countries (except
Japan, where GSM isn't used), buy prepaid SIM cards from local carriers and make
relatively cheap local calls instead of running up huge bills roaming on your own
carrier.” [Claire Pieterek - Computing Unplugged]
“…Today, cell phone customers worldwide are accustomed
to using phones that are exclusively locked to particular service providers,
so the concept sounds like nothing new on the surface. The technology to which
the name refers, Subscriber Information Module (SIM), is a small card which,
naturally, became popular first in Europe, before moving to Asia and then,
finally, North America. It enables a user to store personal information,
including her address book but also her service provider information, on a
small card that slips into a supporting cell phone, generally beneath the
battery case. The purpose of this technology was originally to encode the
cell phone user's service data on a portable card that can be transferred
between phones. ” [Scott M. Fulton III - Tom's Hardware Guide]
“…As users of GSM phones know, their instruments include
a removable circuit called a SIM (subscriber information module) card.Ê The
SIM card carries account information, such as a phone number, billing authorization
data from a carrier and personal information like the owner's phone book.Ê Any
SIM card (or at least one of the current 3.3 volt types) can work in any GSM
phone, as long as the phone has not been programmed by a carrier to accept only
its own SIMs.” [Tech-News.com]
“…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 even when you're using a borrowed phone. Upgrading your phone
is as simple as slipping your SIM card into your new phone.” [USTronics]
