[VoIP] DTMF question

[Jayson Smith]

Hi all,
Got a puzzling one for you guys. I recently got three Sipura SPA-2000 units,
and am using one, and like it. Just for the heck of it, I set
dtmfmode=inband for both lines in sip.conf, and have both lines set for
inband DTMF in the SPA. Still, calling one line from the other via my
Asterisk system, when I hit a touchtone on either phone, the other gets a
tiny blip of the original tone, then, once I let up on the button, a
regenerated, fixed-duration touchtone is heard. In other words, as far as I
can tell, inband DTMF isn't really working. My codec choice is Ulaw, so that
shouldn't be a problem. Any thoughts?
Thanks.