GSM mobile telephone standard

The development of the GSM mobile telephone standard can be traced back to a standardisation committee which in 1982 founded the European Postal and Telecommunications Services Bill under the name "Groupe Special Mobile". The GSM standard specified cellular mobile telecommunications systems with digital switching and transmission technology for language and data (up to 9,600 bit/s per channel and higher). GSM systems offer extensive additional performance characteristics. This includes, for example, call waiting signals, the ability to alternate between callers and the ability to make conference calls with three parties. Furthermore, it is possible to transmit text messages with up to 160 characters which appear in the display of the receiver as text (SMS = short message service).

The first GSM networks were set up in a number of European countries in 1990. Up to mid-1999 more than 300 GSM networks had been installed in over 130 countries. In 1992 in Germany the mobile phone operators T-Mobil (D1 network) and Mannesmann Mobilfunk (D2 network) started to commercially exploit the D mobile telephone networks which were both based on the GSM standard.

Inexpensive handsets
The letter "D" was added to the previously existing German mobile phone networks (A, B and C). The introduction of the D networks promoted the first inexpensive mobile phone handsets. The compact design of these handsets made them suitable also for use outside vehicles. These mobile devices enabled the change from a "car telephone network" over to mobile telephony as we know it around the world today.