Asterisk Decode of DTMF without the requirement of "Carrier Squelch" input

Ok, I am very new to Linux, Asterisk and Nodes!
I have made a PC based radio less node with a USB CM108 sound card, using the PC iso.
It is all working great, DTMF decoding perfect, connect, disconnect etc etc
When I disconnect from a node (radio link to a local repeater) using the DTMF microphone it all works, BUT, it momentarily keys the local repeater and I hear very short virtually notched out DTMF tones.
As I said, it all works but there must be a way of Asterisk decoding my DTMF tones without the requirement of the COS/PTT input on pin 48 of the CM108 chip!
Connects and Disconnects via Asterisk CLI work perfect with no repeater key ups.
Any advice much appreciated.
Gary.

What channel driver are you using? I presume simpleusb? Have you calibrated the audio using the simpleusb-tune-menu?

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Nathan Hardman

nhardman1428@gmail.com

N8THN@ARRL.NET

Hi Nate, thank you for replying. Yes Simpleusb driver. I have kind of “calibrated” the mic audio (normally would be receive audio!) using the level meter in the tune menu. Mic audio is peaking to just over the mark and the dtmf tones are much lower as required. The mic audio sounds good monitoring the local VHF repeater and on a Parrot node.
Asterisk CLI shows decodes 100% of the time and it does connect and disconnect great too.
Just can’t understand why Asterisk would need my PTT. I thought just being on the audio input would be sufficient!

Hi Gary,

AllStar will key up your node andy any connected nodes when pressing PTT and touch tones are quickly muted. So this sounds normal. As for why COS/PTT is needed, that because the channel driver (SimpleUSB) has to see COS (and perhaps CTCSS) to know it has process touch tones. The CLI on the other hand, is happy with a carriage return.

An alternative to the CLI is to use Allmon. Allmon is a web-based application for monitoring and controlling AllStar nodes. I seldom use touch tones as Allmon is much more convenient. Allmon may already be installed on your node and only needs to be configured. Let me know if you’re interested and/or need assistance getting it working.

Thanks Tim,
A very clear answer for me.
So the simpleUSB driver needs my PTT to process the DTMF.
I am very pleased with this node application on my old unused PC. It’s been a crash course in Linux, Asterisk and Allstarlink Nodes!
I will now investigate Allmon. Thanks again.
Gary VK6GC

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