GENERAL TELEPHONE OR DIGITAL KEYPHONE CONNECTING CIRCUIT IN DIGITAL KEYPHONE SYSTEM

摘要

The circuit is for connecting STN to digital key phone system. The circuit includes a) power and current limiter(455) which generates the line-driving voltage, b) the second codec(451) which encodes and decodes the signal passed through B2 channel allocated transmitter of digital key phone system, c) ringer(453) which generates ring signal to call by control signal generated from micom of digital key phone system, d) analog matching part which matches analog signal by the 2/4 wire transformation connecting to codec and transmitting/receiving line(Tx,Rx), e) power supply(454) which supply the line voltage to be easy to transmit the transmitting/receiving signal to STN, and f) the relay to control the supply of ring signal frm STN.