[Freeswitch-users] DTMF bleed through in conference

[Kristian Kielhofner]

Agreed.  Sounds like an analog device not clamping inband DTMF -> RFC
2833 events properly (or quickly enough).

Grab a pcap and look at the audio.  See if you can see DTMF in the
audio stream itself.

On Mon, Aug 15, 2011 at 7:09 PM, Michael Collins <msc at freeswitch.org> wrote:
> Are the devices that send the DTMFs using 2833? Sounds like possibly they
> are using inband. I would get a pcap with RTP of the conference and see
> what, exactly, the device is sending. Some tips for this can be found here:
> http://wiki.freeswitch.org/wiki/Packet_Capture
> -MC
> On Mon, Aug 15, 2011 at 3:48 PM, David Bolen <db3l.net at gmail.com> wrote:
>>
>> I'm encountering what I would probably best describe as some bleed
>> through of inbound DTMF when in a conference, and I was wondering if
>> anyone might have suggestions for likely causes or troubleshooting?
>>
>> DTMF detection itself seems fine, and appears to properly be using
>> rfc2833 (the SDPs all show include "a=rtpmap:101 telephone-event/8000").
>> I get "RTP RECV DTMF" logs for each digit that is recognized.
>> However, a reasonable percentage of the time, some small fraction of
>> the DTMF appears to be heard by the conference as a whole.  Never the
>> whole thing, and sometimes it's a bit distorted (though that may just
>> be due to it being so short).  Almost as if a small portion of a sound
>> sample makes it through.
>>
>> For testing, I'm using internal phones with direct SIP connections to
>> the switch so no PSTN or gateways involved, though it also occurs with
>> a PSTN caller coming in through multiple gateways.  For the internal
>> phones, I've tried both a physical phone through a PAP2T, as well as a
>> PC soft phone.
>>
>> This is with git-868d823 from Jul 29, so a few weeks old but reviewing
>> the more recent commits there weren't any seemingly related to DTMF or
>> conferencing.
>>
>> Any suggestions on places to look or things to try would be most
>> appreciated.
>>
>> -- David
>>
>>
>>
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-- 
Kristian Kielhofner