Re: Touch Tone Blocking

I need to devise a way to keep users from playing touch tones over the

> paging system. If you can suggest a way to prevent users from > sounding touch tones over the paging amplifier circuit post it here or > E-mail direct.

Use a DTMF receiver chip to detect the tones. Feed the PA audio input into the chip and connect the DV output to the PA Mute input. Probably a $5 investment in parts, or a minimal drain on your junkbox :-)

You'll still get a brief burst of tone (20-50msec) at the beginning but the rest of the tone will be muted.

Gordon S. Hlavenka

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Tragically, as many as 9625 out of every 10,000 individuals may be neurotypical

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Gordon S. Hlavenka
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