Hi Brian,
Thanks for your reply,
We are only using
Sangoma cards without echo cancellation, so we are already using our systems with hardware dtmf detection as disabled ( TDMV_HW_DTMF = NO).
Instead we tried on spare
Sangoma card with echo cancellation and hardware detection enabled ( TDMV_HW_DTMF = YES) and found no issues. However if i go with this solution then it would need me to replace more than 100 cards. :(
Using mod_spandsp with the below dialplan example results in more wierd results, i just pressed key 5 and received 4,5 and 8 DTMF on console.
Please suggest if DTMF detection has any more configuration inside spandsp.conf.xml.
<extension name="park_for_dtmf">
<condition field="destination_number" expression="park_for_dtmf">
<action application="set" data="dtmf_verbose=true"/>
<action application="spandsp_start_dtmf" />
<action application="park"/>
</condition>
</extension>
What i found after enabling mod_spandsp is that it tries to evaluate frequencies from entire audio. which in my case can be resource intensive as we do lakhs of calls per day and have 32E1s on single machine.