asterisk users - Apr 2003 - still looking for iconnect configuration help

Folks,

I am still getting really weird results from iconnect. When I connect
using the 7777 prefix that forces compressed codecs my connections work
fine (I connect using AST_FORMAT_GSM).

When I leave out the 7777 prefix, and connect using the codec
AST_FORMAT_ULAW I get the RTP connection, but no incoming audio.

My telephone device is a linejack.

Here are my extension.conf entries:

exten => _1XXXXXXXXXX,1,Dial(SIP/7777${EXTEN}@iconnecthere)
exten => _1XXXXXXXXXX,2,Congestion

exten => _91XXXXXXXXXX,1,Dial(SIP/${EXTEN:1}@iconnecthere)
exten => _91XXXXXXXXXX,2,Congestion

Gregg