GSM (Global System for Mobile communications) is a digital mobile telephony system. A circuit-switched technology, GSM uses a variation of Time Division Multiple Access (TDMA). It digitizes and compresses data, then sends it down a channel with two other streams of user data, each in its own time slot. GSM operates at either the 900 MHz or 1800 MHz frequency band.
The value of GSM to mobile phone customers is the ease of roaming and switching carriers without switching phones. For network operators, the value lies in a wide choice of vendors.
A GSM model is a wireless modem that works with a GSM wireless network., sending and receiving data through radio waves. A GSM modem can be an external device or a PC Card / PCMCIA Card. External GSM modems are typically connected to a computer through a serial or USB cable. A card GSM modem is designed for use with laptop computers and slides into the appropriate slot on the computer. Like GSM mobile phones, GSM modems must have a SIM card from a wireless carrier to operate.
Packet data capabilities were added to GSM with the release of the General Packet Radio Service (GPRS). For network carriers, GSM with GPRS provides a low-cost alternative to voice calls, the Short Message Service (SMS). The Axeda Platform supports GPRS over GSM through pluggable transport adapters installed in the Platform. When receiving messages from and sending messages to tracking assets that monitor assets, the Platform can decode and encode SMS messages.