Before the advent of Automatic Switching, all Telephone Connections were made by hand at the Manual Switchboard, Figure 1. The Calling Customer rang up an Operator, at a Switching Office, which, after knowing the number of the Called Customer, interconnected the corresponding Lines, to Close the Circuit, in order to complete the Call.
Figure 1: Manual Switchboard
As the Telephone Systems became more sophisticated, the Automatic Switching replaced this direct intervention by the Telephone Operator.
Links
- Telephone Switchboard - Wikipedia
- Telephone Switching and Switchboards - IEEE Virtual Museum
- Early Work on Dial Telephone Systems by R. B. Hill
