On Sat, Oct 8, 2011 at 1:42 PM, Tony Graziano <[email protected]>wrote:
> I am seeing some issues with a provider who has sonus equipment as their > UA. As a result, DTMF does not work with Media Services. I think this is a > pretty well known issue within the FreeSwitch community. > > *** from FS wiki > DTMF Problems > > If you are having DTMF problems and Sonus *is in your media path*, you > should make sure you are using the latest version of FreeSWITCH. As of > FreeSWITCH revision 10744, FreeSWITCH auto-detects Sonus end-points and > applies a hack to "fix" the issue. The hack is described as follows (from > switch_types.h): > > Sonus wrongly expects that, when sending a multi-packet 2833 DTMF event, the > sender should > increment the RTP timestamp in each packet when, in reality, the sender > should send the > same exact timestamp and increment the duration field in the 2833 payload. > This allows a > reconstruction of the duration if any of the packets are lost. > > final_duration - initial_timestamp = total_samples > > However, if the duration value exceeds the space allocated (16 bits), the > sender should > increment the timestamp one unit and reset the duration to 0. > > Always sending a duration of 0 with a new timestamp should be tolerated but > is rarely > intentional and is mistakenly done by many devices. The issue is that the > Sonus expects > everyone to do it this way instead of tolerating either way. Sonus will > actually ignore > every packet with the same timestamp before concluding if it's DTMF. > > Note that the version of FreeSWITCH which has this patch auto-detects > Sonus, so you don't need to configure anything. > > *** > > Can someone give me an indication if thus patch is in the sipx current > build or not? If not, does it make sense to include it? > Anyone?
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