[asterisk-users] Asterisk + DTMF + g729

[Chris Hodgetts]

Hello,

I have a SIP provider that only supports the g729 codec.
My ATA is a PAP2 that has the g729 codec built in.
The SIP provider only supports inband DTMF, not sure how they do it over
the g729 codec, but that's not really my concern ;) - I would like to
know given my issues at the end of the post, however it's a lesser issue
to this one.

Selecting anything other than inband DTMF and g729 makes DTMF fail on
the far end, however, using the g729 codec with inband DTMF to Asterisk,
voicemail fails - I understand the reasons why this fails...

When I select the codec to u-law on the PAP2 and my "peer" only allows
g729 Asterisk then does trans-coding which introduces lag and delay and
the far end hears my voice all choppy.
I am using a wireless link back to my ISP.

The PAP2 option: Use Pref Codec Only, is set to No.

What I am wondering, is there a way to tell asterisk to try or force the
PAP to use g729 when its talking via this particular peer and when I am
going internally, or direct to asterisk, to use u-law so that inband
dtmf works with the voicemail.

Basically when I get voice mail, I need to reconfigure the PAP to talk
u-law so I can access voicemail, then return it back to g729 for remote
calling.

This is a side issue however I would really like to get it resolved as
well if I can.

When I call in via my Voice Service Provider and goto DISA, I am
assuming because of the compression, it does not understand the DTMF,
however that's all they support.. what I don't understand is why it
would work outbound, but not inbound...

Any thoughts / comments / suggestions on this would be very helpful, and
I thank you in advance.

Cheers, 

Chris