asterisk users - Dec 2004 - no voice with all sip phones until hold/unhold

Hello everybody and merry xmas.

I have a problem with sip phones calling each other inside the same 
network (no nat, no firewall).

You can make and receive calls and pick them up, but you cannot hear 
anything on any side of the call. But if you press hold/unhold or you 
transfer the call, then everything works as expected.

Ths SIP phones I've tried are Swissvoice IP10s and kphone, it happens the 
same with both of them.

I've tried several codecs to no luck, canreinvite=no, but nothing does the 
trick.

This is my sip.conf:

[general]
context= bogon-calls
port=5060
bindaddr=0.0.0.0
srvlookup=yes

[k-phone1]
type=friend
host=dynamic
dtmfmode=rfc2833
secret=XXXXXXXX
callerid="k-phone1" <601>
context=internal

[phone2]
type=friend
host=dynamic
dtmfmode=inband
secret=XXXXXXXX
callerid="phone2" <602>
context=internal

[phone3]
type=friend
host=dynamic
dtmfmode=inband
secret=XXXXXXXX
callerid="phone3" <603>
context=internal


Can anyone enlighten me?

-- 

Pau