Data Communication - Panasonic KX-T7665AL Service Manual

10.6. DATA COMMUNICATION

Function
The data communication circuit serves the following functions:
Information exchanger between PBX and proprietary telephone, key input information as well as data for the LED control, LCD
control, voice data, etc. This information is continuously exchanged at all times.
Circuit Operation
The data received from PBX is inputted to the comparator (pin 36) built in IC2 through Pulse Trans T1. The threshold voltage
of the comparator is determined by R101 to 103 and inputted to pin 37 and 35 of IC2.
The data to PBX is outputted from pin 38 and 39 of IC2, drives T1 by Transistor Q1 and transmitted.
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KX-T7665AL / KX-T7665X