[Freeswitch-users] Inband DTMF Problem

Klaus Teller klaus.teller at gmx.net
Wed Nov 5 07:08:00 PST 2008

Hi Folks,

It's me again with a DTMF issue. Here is what's going on. I have a remote IVR and i'm writing some code to communicate with it, exercise it, and test it. The remote IVR is playing DTMF as inband. 

Right now, Freeswitch can detect all DTMF digits from the IVR. The interaction between my code and the IVR is essentially  a combination of  playing files and sending and reading DTMFs.

The issue: whenever my code plays a file or send a DTMF digit, the following attempt to read DTMF fails. By failing i mean that there will be a spurious DTMF detected by Freeswitch that was not sent by the IVR.

That is, if i have something like:

sendDTMF("3"); getDigits("38373", "#");  // # is the termination character

After executing the sendDTMF, getDigits fails because it immediately detects a pound. Yet this pound is not sent by the IVR. I can check this by having wireshark running both on the IVR's computer and on Freeswitch's computer.

Any idea what may be causing this problem? Is there some sort of Echo going on or something like that?


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