Foreign exchange

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A foreign exchange (AVSt) is responsible for establishing communication connections to and from abroad. Trunk exchanges that handle transactions with other countries, hot foreign exchanges, in cross-border long-distance lines abroad head exchanges . Long distance switches with international through traffic are called international through switches.
The national telephone network is connected to the AVSt via feeder and receiving lines, where it is connected to the international transmission lines. This can be cables , radio links or satellite links . A number of transmission and switching parameters must be observed at the transfer point to the foreign network .

National network BRD for international connections

Technical status of the following description: electromechanical switching technology from the T 62 remote dialing system (1962) to digitization.

Schematic diagram of international long-distance dialing in Germany from system T 62

The national long-distance network in the FRG also served as a feeder network for outgoing international telephone traffic for the foreign exchanges. It was used as a distribution network for the incoming international connections.

An outgoing international connection was routed via ZIG in the KVST and the subsequent cross lines or via the code path to the AZVST in the area of ​​the own ZVSt.

In larger local networks that were also at the headquarters of an AZVST, the foreign counting pulse generator (AZIG) in the AZVST could also be reached directly via the partially still existing aisle technology.

The AHVST could only be reached directly via a KRW or KRW and HRW if the connection had to be switched directly to the neighboring country due to tariff reasons.

The entire national network was available for incoming connections from abroad.

Via the international direction coupler (ARKpl) of the AZVST, the FGW (remote group selector) of the ZVSt area as well as other ZVSt areas were controlled either via the ZGW code path or via cross paths.

literature

  • Volker Jung, Hans-Jürgen Warnecke (Hrsg.): Handbook for telecommunications. Springer Verlag, Berlin / Heidelberg 1998, ISBN 978-3-642-97703-9 .
  • Martin-Friedrich Haubner: Origin, structure and use of communication networks in Iceland. Diplomica Verlag 2003, ISBN 978-3-8324-7250-4 .
  • Martin Werner: Networks, protocols, interfaces and communication. 1st edition, Friedrich Vieweg & Sohn Verlag, Wiesbaden 2005, ISBN 3-528-03998-1 .

Web links