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 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 dialled "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".
Credits and References:
1) BID 160 placard at the Royal Signals Museum in Blandford Forum, UK.
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