公开(公告)号：CH599731A5

公开(公告)日：1978-05-31

申请号：CH254876

申请日：1976-03-02

Applicant: IBM

Inventor： SCHINDLER HANS-RUDOLF DR ,  VETTIGER PETER

IPC: H04B3/03 ,  H04B1/58 ,  H04M19/00 ,  H04Q1/28

Abstract: This invention comprises a telephone hybrid circuit having two opto-coupler arrangements for transferring voice signals from the two-wire line to a port of the switching system on one hand and from a port of the switching system to the two-wire line on the other hand. In addition, a pair of feeder circuits in the form of current sources comprising active elements are provided for feeding a constant positive direct current to one wire of the two-wire line and a negative direct current of equal magnitude to the other wire of the two-wire line. Each of the current sources includes control circuitry for maintaining a constant ratio between the current furnished by the current source and a control current common to both current sources. A control current path is connected to the output of one of the opto-coupler arrangements for generating a common control current in response to a dc signal and a superimposed voice signal received from a port of the switching system. The other opto-coupler arrangement couples the signals from the two-wire line to a port of the switching system.