asterisk users - Dec 2004 - Grandstream BT100 / HandyTone 286 and Level 3

Hello,

Has anyone gotten a Grandstream BT100 to work with Level 3's 3Tone?

I've been able to get my extension to interface with it, but there is no 
sound
and the call on the GS side terminates prematurely.

Here is the relavent portion of the SIP.CONF

[4007] ; Budgetone BT100
type=friend
insecure=yes
context=test-budget
username=4007
fromuser=4007
callerid=4007
host=dynamic
nat=yes
canreinvite=yes
dtmfmode=info
incominglimit=1
disallow=all
allow=ulaw
allow=alaw

[4008]   ; HandyTone 286 with POTS phone
type=friend
insecure=yes
context=test-budget
username=4008
fromuser=4008
callerid=4008
host=dynamic
nat=yes
canreinvite=yes
dtmfmode=info
incominglimit=1
disallow=all
allow=ulaw
allow=alaw

I can send the history file - but it's quite large...

Thanks in advance...

...Paul