DESCRIPTION

The LS656 is a monolithic integrated circuit in 16-lead plastic package to replace the hybrid circuit in telephone set. It works with the same type of transducers for both transmitter and receiver (typically dynamic capsules). Many of its electrical characteristics can be controlled by means of external componentsto meet differentspecifications. In addition to the speech operation, the LS656 acts asan interfaceforthe MFtonesignal(particularly for M761 C/MOS frequency synthesizer).

. PRESENTS THE PROPER DC PATH FOR THE LINE CURRENT, PARTICULAR CARE BEING PAID TO HAVE LOW VOLTAGE DROP

. HANDLES THE VOICE SIGNAL, PERFORM ING THE 2/4 WIRES INTERFACE AND CHANGING THE GAIN ON BOTH SENDING

AND RECEIVING AMPLIFIERS TO COMPEN SATE FOR LINE ATTENUATION BY SENSING EITHER THE LINE CURRENT OR THE LINE VOLTAGE. IN ADDITION, THE LS656 CAN ALSO WORK IN FIXED GAIN MODE

. ACTS AS LINEAR INTERFACE FOR MF, SUPPLYING A STABILIZED VOLTAGE TO THE DIGITALCHIP ANDDELIVERINGTO THE LINE THE MF TONES GENERATED BY THE M761