Swarms of control lights on every wall: the place looked the inside of a trunk exchange.

The tower is one of many buildings and trunk exchange centres that belong to SingTel.

Packet switches were installed at major trunk exchanges in most major conurbations in the UK.

Established in 1976, the Palakkad unit of ITI Limited manufactures large digital switches and digital trunk exchanges in collaboration with M/s Alcatel of France.

The last electromechanical trunk exchange (in Thurso, Scotland) was closed in July 1990-completing the UK's trunk network transition to purely digital operation and becoming the first national telephone system to achieve this.

This code was used for STC's BXB1121 which was a four-wire version of the French Pentaconta system, used by the British Post Office for main trunk exchanges.

On 1 January 1973 the States of Jersey took over the trunk exchange and cable network from the Post Office Telephones and assumed a monopoly for the supply of telecommunications services on the island under the Telecommunications (Jersey) Law 1972.

In the middle of the 1980s the former telecommunication office at of Rottweil installed two directional antennas on Lember Tower for the realization of a passive repeater microwave link between the communications building in Rottweil and the trunk exchange, situated at station road in Gosheim.