Overview

The system now referred to as GSM started life as the Groupe Speciale Mobile. Later this was changed to represent its global nature, while keeping the same initials, to Global System for Mobile communications.

The aim was an initiative to develop a digital mobile phone system that would support roaming across country borders and also provide improved capacity when compared to the analogue systems that were then in use. As the press had made much of the lack of security of some of the analogue systems that had been in use, with more than one high-ranking dignitary having their calls listened to by outsiders, call privacy and security were also high on the agenda.

The goals set for the system were tough, as no digital system had been launched before and neither had any attempts at roaming on this scale been considered. The original aim was to use spectra in the 900-MHz region, but since its initial launch further bands have been used at 1800, 1900 and, more recently, 800 MHz. Originally the systems using the high-frequency bands were given the names DCS 1800 (Digital Communications System) and PCS 1900 (Personal Communications System). Now they are simply referred to as GSM 1800 and GSM 1900 respectively.

The system has been a considerable success, far outstripping the take-up by any other network beforehand or currently available. In early 2004 the system had over a billion subscribers, and this figure has continued to rise.

Part of the success of the GSM...