In Band DTMF signalling on Ext answer

Hi all,
I am looking for some help to find a way to get FreePBX/Asterisk to send an in-band DTMF sequence after an extension answers.
I know it sounds strange, but essentially I have a base radio interface that uses DTMF signalling to initiate a call to another mobile radio station. The extension of the base radio will auto answer after the first ring and I am trying to get the system to automatically send the DTMF sequence to initiate the call right at this point so the call to the mobile radio station can be triggered from the base. Any help would be greatly appreciated!! I am not very fluent with FreePBX - I’ve made the internal Extensions work fine, but this seems a bit more involved than the basic setup I have created.
Many thanks :slight_smile:

perhaps googling ‘dahdi ham radio’ will help

Hi Dicko,

Thank you for your reply.
I am well aware of this module, thats not what I am looking for, and is not what I need… I already have the RoIP interface (Omnitronics IPR110+) which feeds to an Omnitronics 619DSRI for multiple 4 wire E&M interfaces across multiple P25 & DMR networks, with a remote console interface.

All I need is for the DTMF sequence to be sent in band when the RoIP interface answers…

This isnt for Ham radio…

Ok, after a lot of experimenting, the solution was actually quite simple.
I thought I would add it here just in case anyone else comes looking for this solution to tie a Codan HF into a FreePBX system with an IPR110+ and a Codan 3032 Crosspatch. Since Codan no longer make the 3033 TI units - this seemed like the only real way to get the bridge between the 2 systems to work where an incoming SIP/VoIP call could trigger the ALE/CALM function of the radio while it is in scan mode on an ALE 2G network.

Essentially the extensions_custom.conf was edited to have:
[custom-dtmf-after-answer]
exten => 123,1,Dial(PJSIP/123,D(wwwwwwww*0199##))
exten => 123,n,Hangup()

[from-internal-custom]
exten => 123,1,Goto(custom-dtmf-after-answer,123,1)

Where ‘123’ is the extension, ‘199’ is the SelCall/ALE address number of the primary mobile radio making *0199## the command for the 3032 to initiate a call to that specific address.

Then set the extension 123 to use in-band DTMF instead of RFC4733. under ‘Connectivity>Extensions>123>Advanced>DTMF Signalling’

Functionally, this works perfect for my particular setup as traffic across any of the UHF/VHF networks can flow freely without keying up the Codan base. The VHF and UHF MSU’s all have DTMF & SelCall so an end user can trigger the HF link if required, or modify the DSRI patching matrix across predefined linking combinations of either of the 3 radio bands.

As a final note, I recognize that this is super specific to the needs of me and my network’s requirements, there are quite a few other config changes made to FreePBX and the Radio/Audio hardware to make this all work correctly, but if anyone finds themselves here after a google search for a similar sort of thing, please feel free to reach out to me if you need any further information. I learned quite a lot from this endeavour :slight_smile:

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