DTMF not working M208

[sailor]

Hello,

I have a 16 Channel UHF M208 and a HMN103B DTMF mic. It doesn't appear to send any DTMF tones. Is there something that needs to be set in RSS to enable DTMF encode?

[Al]

The DTMF mic takes care of muting its mic, sending the mic-generated DTMF tones on the mic line, and keying the M208's transmit while tones are being sent. The short answer is: no, there's nothing in the RSS that affects DTMF transmission or operation.

[sailor]

The mic only keys the PTT when the keypad is pushed. The mic itself emits a high bird-like tone when each key is pressed, but it's not DTMF. Any ideas?

[Bill_G]

If it's a working TMN1032, then it is a fully capable, self contained dtmf mic that puts out dtmf tones in any model of radio it can plug into without any changes to the radio programming. And it does indeed have a sharp, high pitched side tone when a key is pressed rather than dtmf tones which I always thought was strange. You'll will have to listen in another radio tell if it is properly generating tones. If it isn't, but you can talk through it, then it's broken.

[jackhackett]

And it does indeed have a sharp, high pitched side tone when a key is pressed rather than dtmf tones which I always thought was strange.

I would imagine that they used a little piezo buzzer to indicate a button press. It was probably less expensive to do it that way at the time these mics were designed.

[sailor]

Thanks for the help. I got the schematic, and compared it with the mic and someone had made modifications of some kind. Some jumper leads were added, etc. I snipped them and everything is great. No idea what they had tried to do!