GSM (Global System for Mobile communication) is a digital mobile telephone system that is widely used in Europe and other parts of the world. GSM uses a variation of time division multiple access (TDMA) and is the most widely used of the three digital wireless telephone technologies (TDMA, GSM, and CDMA). GSM digitizes and compresses data, then sends it down a channel with two other streams of user data, each in its own time slot. GSM uses three frequency bands.
GSM 900 - operates in the 900 MHz frequency range and is the most common in Europe and most of the world.
GSM 1800 - operates in the 1800 MHz frequency range and is found in a growing number of countries already using GSM 900.
GSM 1900 (also called PCS (Personal Communication Services) 1900) - is used in the United States and Canada.
GSM is the de facto wireless telephone standard in Europe. GSM is available in more than 200 countries, according to the G
SM MoU Association. Since many GSM network operators have roaming agreements with foreign operators, users can often continue to use their mobile phones when they travel to other countries.
