WB800 Piped Music Distribution

This description is added for completeness should anyone be trying to enquire what the WB800 was.

The WB800 was designed to distribute 'Piped Music' to offices and shopping centres. I think this was conceived as a money spinner, but it never appeared to take off. Music from a central source was sent out by dedicated audio circuits to exchanges that had a customer(s) subscribing to the service. A 144 KHz carrier generated in the exchange was amplitude modulated with the audio and distributed via the normal telephone line to the subscribers premises. Filters like thoses used by the civil defence carrier network were used to separate the carrier from the phone.

. . . Well thats all it was !! - Nothing to do with UK Civil Defence or the Cold War, which are described on the link below.