Junctor

A junctor is a circuit used in analog telephone exchanges, including the Number One Crossbar Switching System, Number Five Crossbar Switching System, Panel switch, 1ESS switch and other switches.

In early electromechanical switches including panel switch, a "district junctor" handled supervision and talk battery duties for outgoing calls, similar to the duties of the cord circuit of manual exchanges. The junctors for incoming calls were simple three-wire connections between the incoming frame and the line frame. In the later electromechanical 5XB switch, junctors only consisted of three wires to connect the two legs of a call: the line and the trunk, of which the latter supplied all talk battery and supervision.