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call progress decoder problem

call progress decoder problem

call progress decoder problem

(OP)
I am from the Philippines and getting parts here is difficult. I have built a telephone patch but it stays off-hook if the call was not completed(answered) thus hanging my phone till it is reset manually. I think I can resolve this by detecting the busy tone at the end of the call. I have searched the net and found that the Call progress tone decoder IC may be my answer but we have none of those here in the Philippines. Since a busy signal as I understand has a 0.5sec tone pulse ON and 0.5sec OFF is it possible to make a circuit using common IC like the op-amps or 555timers or ... to detect this pulses to determine that the call was terminated and reset my telephone.

Thanks

arliesantos@yahoo.com

RE: call progress decoder problem

I think you need to decode the specific tone first, then detect and measure the envelope, which will distinguishe between a regular busy and a fast busy.

TTFN

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