[Freeswitch-users] mod_callcenter and start_dtmf

Mimiko vbvbrj at gmail.com
Wed Jul 10 22:48:36 MSD 2013


Recently I have found problem which was in callcenter application. 
Agents randomly had heard a beep sound like calling members where 
pushing some number to send a dtmf done. This was annoying, because this 
was in a middle of conversation. This tone had appearing randomly not on 
every incoming call to callcenter. It was high volume of 0.5-1 sec long. 
I couldn't track the source of this sound, as in the resulting recorded 
file of the conversation there where no suspicious sounds, nor a beep 
from callers, nor the beep from or to agents. So I was lost. Several 
days ago I remembered about using start_dtmf application on incoming 
calls from phone provider because the do not use rfc standard for dtmf. 
More strange thing was that this strange beep sound didn't appear on 
regular incoming call to some extension. It was only when external 
callers from phone provider were calling into callcenter number. So I 
used stop_dtmf just before sending incoming call to callcenter 
application. With this command those strange beeps disappeared.

Then I've changed start_dtmf to spandsp_start_dtmf and didn't use 
spandsp_stop_dtmf. Beeps does not appear too. So there seems to be a 
problem with core handling of in-band dtmf with start_dtmf aplication 
when call is routed into callcenter, and the callcenter bridged the call 
to the agent. Should I rise an issue to the jira, or this is an internal 
known issue of core dtmf handling and will not be resolved?

Mimiko desu.

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