[asterisk-users] DTMF

[Jeff LaCoursiere]

On Fri, 17 Apr 2009, Jeff LaCoursiere wrote:

>
>
> On Thu, 16 Apr 2009, Kevin P. Fleming wrote:
>
>> Jeff LaCoursiere wrote:
>>
>>> So may I assume that dtmfmode is inband only over IAX (since adding
>>> compression seems to have killed it?).  That would suck.
>>
>> No, DTMF is always out of band on IAX2, as long as Asterisk knows the
>> DTMF is happening; if the DTMF is inband on the SIP channel, and
>> Asterisk has been configured for non-inband DTMF on that channel, then
>> it is not aware the DTMF is even present, so it just stays in the audio
>> stream and gets compressed (and destroyed).
>>
>> You can verify this by adding the 'dtmf' logger channel to your console
>> or a log file, and checking whether Asterisk is even aware of the DTMF
>> events on the SIP channel.
>
> I went ahead and switched to SIP just for grins, and made sure
> "dtmfmode=rfc2833" is in the peer config on both sides and in the entry
> for the phone.  So now it is:
>
> polycom501---SIP/ulaw--->ast1---SIP/g729--->ast2---IAX/ulaw--->ITSP
>
> looking at DTMF debug on ast2 I have:
>
> [Apr 17 15:18:06] DTMF[21585]: channel.c:2226 __ast_read: DTMF begin '5'
> received on SIP/ahriise-0882f470
> [Apr 17 15:18:06] DTMF[21585]: channel.c:2236 __ast_read: DTMF begin
> passthrough '5' on SIP/ahriise-0882f470
> [Apr 17 15:18:07] DTMF[21585]: channel.c:2148 __ast_read: DTMF end '5'
> received on SIP/ahriise-0882f470, duration 200 ms
> [Apr 17 15:18:07] DTMF[21585]: channel.c:2195 __ast_read: DTMF end
> accepted with begin '5' on SIP/ahriise-0882f470
> [Apr 17 15:18:07] DTMF[21585]: channel.c:2211 __ast_read: DTMF end
> passthrough '5' on SIP/ahriise-0882f470
>
> Does this look like inband or out of band signaling?

Looking at it a little closer, some of the debug lines look different:

[Apr 17 15:18:07] DTMF[7041]: channel.c:2226 __ast_read: DTMF begin '1' 
received on SIP/ahriise-0882f470
[Apr 17 15:18:07] DTMF[7041]: channel.c:2230 __ast_read: DTMF begin 
ignored '1' on SIP/ahriise-0882f470
[Apr 17 15:18:07] DTMF[21585]: channel.c:2148 __ast_read: DTMF end '1' 
received on SIP/ahriise-0882f470, duration 200 ms
[Apr 17 15:18:07] DTMF[21585]: channel.c:2184 __ast_read: DTMF begin 
emulation of '1' with duration 200 queued on SIP/ahriise-0882f470
[Apr 17 15:18:07] DTMF[21585]: channel.c:2296 __ast_read: DTMF end 
emulation of '1' queued on SIP/ahriise-0882f470

Emulation?  I am getting more confused by the moment.

j

>
> I am starting to think the issue is actually at the ITSP, as I saw every
> digit I pressed in the CLI on ast2, and yet the AT&T conference line I was
> calling only recognized 3 out of six digits.
>
> Thanks,
>
> j
>
>
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