AF signal connecting device for telephone exchanges - feeds signals through modulator at two=wire to four-wire hybrid junctions

摘要

Pulse train patterns produced by an electronic generator are in the form of DC voltage pulse signals corresponding to individual AF signals. They are each applied to a signal line in a bunch of lines. A centrally controlled electronic selection decoder is connected to the signal line bunch at each AF signal input point, esp. at the two-wire to four-wire hybrid junctions. It selectively connects a signal line to a modulator(M) by which an AF signal (eg 800Hz) in inductively fed into the speech wires in the rhythm of the pulse train pattern of the selectively connected signal line.