We are restoring a 1963 manual "control Line" telephone exchange as part of the BBC outside broadcast van.
The problem revolves round the jack cords which, to quote from the handbook, are "self retracting" Normally the cords would retract by gravity but in this installation there is no room for that. I visualise some sort of coiling arrangement, there is only about 6 inches under the desk top for this.
So the question is was there a "standard" device for this or did Pye make their own??
The telephone control line system is better known as magneto ringing and the panel has a set of dolls eye indicators for incoming calls.
More can be found on the projects website
www.mcr21.org.uk