Caller ID

[sirvo]

Hello you all....

I've built this caller ID using a 16F877 and MT8870 (dtmf decoder).

When I get a phone that is online with the decoder and press the buttons, the LCD shows what numbers are being pressed...ok until that....

The problem is: when I receive outside callings, it does not work.

Well, the service of caller ID is working because there is another phone that detects the caller's number.

Any ideas of how to solve this?

Thanks in advance!!

[muddy0409]

The CID info is not in DTMF. It is 1200bps serial ascii data which comes in between the first and second ring. IE "ring-ring (or just ring if not GB or Au or other countries that use double ring ringing)-CID burst-ring-ring etc"

you probably need a modem chip to read it, or a dedicated CID decoder chip. I believe you can get DTMF decoders with built in CID decoding.


Hope this helps.