DTMF Tones not Recognized by Node

App_rpt-users
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DTMF Tones not Recognized by Node

Is there a particular setting that I am missing? I am unable to control my hotspot node (AURSinc) via DTMF tones. The node works fine with commands from the ALLMON3

Thank you

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Have you tried sending the DTMF tones from more than one radio? Sometimes you can get a rogue remote radio that doesn’t work. Are the DTMF tones being sent by automation. i.e. via a macro. Or are the tones being sent manually on the keypad. Sometimes the RX audio levels, if set too high, can prevent the incoming DTMF tones from being decoded. So dive into the ‘Interface Tune CLI’ menu and wind down option 2 (Set Rx Voice Level…) to something low like 100 0r 150.

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If everything else about your node is working, DTMF decode issues are almost always an issue of over-driven receive audio.

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Thank you! Yes all else works

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DTMF tones issue is almost always a problem with the receiver de-emphasis setting.

  • Run simpleusb-tune-menu, and first go to Option 2 and double check your receive audio level as mentioned previously. When you transmit from your radio and speak at full volume, set that level to where it max’s out at 5 Khz. of deviation. Option W to write, then Option 0 to Exit.
  • Next, from the command line run “asterisk -rvvv” in order to look at node activity in a verbose mode. Key your radio and go through ALL the DTMF digits, including A,B,C,D and you should see EVERY character show up. If they all don’t (usually an entire column or row) then your Rx. de-emphasis is set incorrectly.
  • Exit and run simpleusb-tune-menu again, and select the De-Emphasis option to change it.
  • Run Option 2 again to double check the Rx. audio level. W to write and 0 to Exit.
  • Run asterisk -rvvv and check the tones again and they should all decode.

Realize that FM radios pre-emphasize TX audio by 6db/octave to improve the signal-to-noise ratio on the other end. Receivers have to then de-emphasize the audio to flatten it again, rebalancing the audio curve. In the process it also de-emphasizes noise (hiss, etc.). If you don’t de-emphasize correctly, your tx. DTMF tones are skewed with the higher tones being louder, and the decoder won’t work properly. Let us know if this works.

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