Model: AN/TTC-56B(V)3

Properties:

A telephone office having switching facilities for connecting any manual (nondial) telephone station to any other telephone station within its area. The switching is accomplished manually by means of a jack termination in a switchboard equipped with cord circuits or switches, and supervisory circuits. May include a dial. It generally has trunking facilities to and from other central offices for making connections to telephone stations in those offices. The central office includes all equipment required to serve the lines having a common office name. Does not include the lines from the central office or the telephone stations.