The BID 160 was a complete secure speech unit containing both the vocoder and the key generator. It was designed as a secure speech system for use on 4 wire telephone circuits at UK Government level. This system was used from the early 1960's until the late 1970's."
Another submission provides a few more details on the system. "The Pickwick network was used over Post Office landlines. To access the Pickwick network from MoD Main building, the user dialed "8" on their secure telephone. The call was then connected to one of four BID160s fitted with auto secure switching that followed the secure state of the remote BID160. Because these were in an unmanned exchange room they needed the automating switch to secure the other end of the speech link. There was no need to encrypt within the building as the whole installation was "RED".
To access overseas, the user dialled "0" and was connected via a BID-820 Vocoder at the D.C.N Digital Exchange (R.A.F.). and were then connected via a KG13 and satellite link to the overseas station".
|The Pickwick telephone, circa 1960. Among one of its uses was to keep transatlantic communications secure between US president John F Kennedy and British prime minister Harold Macmillan during the Cuban missile crisis of 1962.|
|Pickwick phone showing operating instructions|
|Photos in this table via E and T Museum|
|Pickwick components. Click on image to enlarge.|
|Front cover of manual. It is stamped January 1961|
|Both photos in this table via Twitter.|
Credits and References:
1) BID 160 placard at the Royal Signals Museum in Blandford Forum, UK.
2) Pickwick telephone photos https://eandt.theiet.org/content/articles/2019/07/