Now let us look at the GSM (Global System for Mobile Communications) and see what it has to offer.
GSM has the best security and privacy features available. GSM offers unrivaled call privacy and fraud prevention. In GSM networks, an encryption algorithm scrambles the digitized voice transmission between the handset and the GSM transmission site. This scrambles information is firstly hard to trace and secondly nearly impossible to unscramble without the encryption code stored in the smart card of the transmitting phone.
All GSM phones contain a SIM. The SIM (Subscriber Information Module) card - a.k.a. "smart card" holds All the phone settings, and the subscribers information, phone number, personal security key (PIN) and other data necessary for the handset to function. The greatest advantage of the SIM is that, since most service providers and mobile set manufacturers follow industry standards, it can be switched from phone set to phone set without any problem.
The SIM card also acts as a security device as it contains the decoding information necessary to decode the encrypted signals sent by the phone to the transmission tower. This makes it virtually impossible to scan or clone a GSM set. The SIM (smart card) is housed inside each handset, and is the brain of the set. It tells the set what to look for, where to look for it and what to do once the network is found. The SIM contains information about the service provider, the rate package, services features applicable and your personal information such as preferences, contact numbers, reminders etc.
Smart cards are available in two shapes. One is the chip itself which is currently being used by most mobile phone manufacturers or the bigger credit card style card. The larger card actually is a housing to hold the chip and goes directly into some sets. Other sets require that you remove the chip from the card and place it directly into the space provided inside the phone.
The biggest advantage of a GSM phone, in addition to the ones mentioned above, is national as well as international roaming. Since many wireless service providers are operating globally a GSM set registered in one country can be used any where in the world provided that the service provider has operations there or that the service provider has a contract with other service providers operating in the area to share customers.
