Section of a CB1 manual telephone exchange switchboard with positions for three operators, unknown maker, British, 1925-1960. In use at Enfield Telephone Exchange 22 July 1925 to 5 October 1960 ...

To save the telephone companies money and to serve better those communities which have both the new dial and the old manual telephone service, Bell Telephone Laboratories invented a device which saves ...

While today’s data centers are largely homogenised grey boxes differentiated by facade color, the UK’s telephone exchanges ...

AT an ordinary or manual telephone exchange, as is generally known, the subscribers' lines terminate on “jacks,” and are put through to each other by means of “plugs” and flexible conductors. The ...