PERFECCIONAMIETOS EN US SISTEMA DE INTERCONEXION POR MANDO A DISTANCIA

摘要

A DTMF encoder at a central office is connected to a spare pair of a feeder cable for remotely controlling with a 5-digit number a series of relay coil matrices where the coils perform latch and release functions for 50 latching relays in each matrix. Two of the digits select the matrix and two other digits select the relay coil to be energized. The fifth digit selects the crossconnect box or pedestal from a plurality of the same. The 50 relays are connected in pairs to serve 25 incoming pairs, each pair of relays being arranged to selectively connect its associated incoming pair to any one of three corresponding outgoing pairs or terminals. Energizing current is supplied to a selected coil only upon receipt of the last of the five digits and only for a brief interval. Power for the remote apparatus is supplied from the central office via a phantom circuit over the same spare pair.