Acronym for Global System for Mobile communication
International standard used for digital mobile communication.
GSM uses a variation of TDMA and is the most widely used digital telephone technology. GSM digitizes and compresses data, then sends it down a channel with two other streams of user data, each in its own time slot. It operates at either the 900 MHz or 1800 MHz frequency band.
GSM is the de facto wireless telephone standard in Europe. GSM has over 120 million users worldwide and is available in 120 countries, according to the GSM 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.
Click here to access a GSM Tutorial - GSM Tutorial
Click here to access a tutorial on SMS, a protocol related to GSM - SMS Gateway