RELIANCE MASTER or EXECUTIVE INTERCOM STATION, 1970's

Office Telephone system with no external line connections.
Transistorised amplifier for microphone in the front for hands free use.
Speaker underneath.
Usually fitted in senior managers and directors offices.

Your comments:

• This is a master or executive intercom station it was usually fitted in senior managers and directors offices. The other stations were handset types with 10 buttons or 20 buttons allowing you 11 or 21 stations. The calls between ordinary units were non secret and calls from these master stations were secret and if a master was calling you up to three could be fitted. A red green or White lamp lit up on your intercom unit. Either 15 way or 25 way cable was used with a separate triple core cable from each station to each master station to give a private circuit. 11 or 21 wires were home lines and the three others were thicker and called Common Carbon + and Talking Zinc - 3v and Ringing Zinc - 6v. The triple was a separate speech circuit to the master bypassing the multicore cable. Your master station is one of the 1970's models and is not a switchboard.
  I served my apprenticeship with Reliance which was a subsidiary of GEC England.
  .......... Ronald Murray, Kirkcaldy, Scotland., 28th of December 2009
  
  

A0048