Outbound DTMF issue with aastra 480i

[chuckjuhl]

I am having a problem with DTMF working reliably outbound using Aastra SIP phones.

We have 6 Aastra 480i and 4 Aastra 480i CT phones. The RTP settings on all phones are:
RTP Port - 3000
Basic Codecs - unchecked
Force RFC2833 Out-ofBand DTMF - unchecked
Customized Codec Preference List - (empty)
DTMF method - RTP
Silence Suppression - unchecked
The Extensions are all set to dtmfmode=RFC2833 in freepbx
The trunk is vitelity. The SIP PEER info is:
type=friend
username=*******
secret=*********
fromuser=********
trustrpid=yes
sendrpid=yes
context=from-trunk ; (this could be ext-did or from-pstn as well)
canreinvite=no
host=outbound1.vitelity.net
disallow=all
allow=ulaw&gsm
DTMF=inband

There is no firewall issue. The box is on a COVAD T1 with a static, public IP.

On the 480i's. if I set the RTP settings to RFC, voicemail and other system features that require DTMF are accessible, but outbound DTMF is still unreliable. Same issue with setting RTP on the Aastra's to "Both", except that the DTMF problems appear on different called numbers (for instance, Walgreens IVR now works but BofA doesn't). If I set the RTP settings to SIP Info, outbound DTMF works reliably, but then I cannot access trixbox voicemail. I do not have this problem with Grandstream phones with DTMF set to "in-audio" and RFC2833."

Any idea how to fix this problem? If I can't fix it, I'm going to have to send all of the Aastra phones back and exchange for Gransdtreams or Cisco's.

 

[jroper]

This is unlikely to be a problem with the phone.

I would suspect that you should use RFC2833 all the way through.

Joe

 

[chuckjuhl]

Been there, done that.

I did try RFC2833 all the way through. The Grandstream phones are happy with that (so long as DTMF is set to both in audio and RFC2833 at the phone). But the Aastra phones won't do outbound DTMF at all - although the voicemail works.

The only real difference between the Aastra phones and the Grandstreams in this situation is that the Grandstreams provide for sending DTMF in audio, where the Aastras don't appear to. I do know that to get fully finctional DTMF on the vitelity trunk, the Grandstreams have to have DTMF set to both in audio and RFC2833. Otherwise they experience the same issues as the Aastra's. If I could somehow get the Aastra's to transmit DTMF in audio as well as RFC2833, I think the problem would be solved.

Any other ideas? Anyone out there using Aastra phones with a Vitelity trunk and have fully functional DTMF?