The caller number display device circuit

Published:2011/6/7 10:36:00 Author:qqtang | Keyword: caller number, display device | From:SeekIC

The device works with the phones that haven't got the functions of display, which can display caller number so that people can check if the called number is right.See as the circuit, the dialing generates DTMF signals and the signals are decoded by decoder CM8870P1(IC1), then the phone number BCD codes are generated, the BCD code of each number is locked in the according latch. This circuit can display 10 bit phone numbers. The first bit of the number is locked in IC5A(1／2CD4508), the second is locked in IC5B, etc.



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