Originally Posted by Arthur P. Bloom
A friend who collects old phone stuff, but who is not a member of this forum, has asked me to forward this request:

Curiously, it contains a Mitel Touchtone receiver chip and a Zilog Z8 MCU.

I'd like to find out what purpose they serve in an audio power amplifier. Presumably there is some DTMF code sequence which performs some special function. There's no way to determine the code sequence without a more detailed user or installer doc. than what I have.

Wondering if it's proprietary. The Z8 is a micro controller, so there is something going on other than the amp. My guess is that it's a programmable tone generator. Program the type of tone and schedule via DTMF. If you have the amp it would be fun to do a tear down and see how it's connected. Won't tell you what the DTMF sequence is though if I'm right.

-Hal

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