Each new cellular phone generation improves the technology from the previous generation. The difference between a second and third-generation phone goes beyond the type of subscriber identity module used by the phone. A 3G phone can download information faster and with higher security than a 2G phone. A 2G SIM card is the type of SIM card required for use with 2G handsets, and a 3G SIM is the type of SIM card required for use with 3G handsets.
The SIM card contains your subscriber information. The integrated circuit on the SIM card, however, does not control any functions on your phone. The SIM card simply offers a gateway for your device. You can only access the SIM card if you have the correct PIN code, and SIM cards use Global System for Mobile Communications cellular networks. The memory on a SIM card can also store a limited amount of data such as your phone’s contact information.
SIM cards come in three different sizes: full, mini and micro. The size specification only affects the physical dimension of the card, not its functionality. In other words, the size of the SIM card does not affect how the SIM card functions only the device that you can use with the SIM card.
The first generation of GSM mobile phones allowed voice communication. The second generation of phones using GSM technology originally entered the market in 1991. The 2G technology uses different bands of the GSM spectrum, including Time Division Multiple Access and Frequency Division Multiple Access, to accommodate voice and data transmission. The 2G networks, however, could not keep up with the increased demand for available bandwidth; 2G can transfer data up to 300 kilobits per second providing insufficient speed for media intensive communications and applications. The 2G technology also uses an A5 ciphering algorithm for security and 200 kilohertz for voice transmission.
The standard for 3G mobile phones fulfills the specifications established by the International Telecommunication Union for International Mobile Telecommunication-2000. To receive a 3G classification, the network must transfer data at a minimum of 144 kilobits per second for moving traffic, 384 kilobits per second for pedestrian traffic and 2 megabits per second without any traffic. The 3G uses KASUMI for the encryption of the authentication process and the 1.25 megahertz channel for voice transmission.