Mine

[channels]
;;General options
relaxdtmf=yes
busydetect=yes
busycount=4
immediate=no
cidsignalling=dtmf
cidstart=polarity
sendcalleridafter=2
usecallerid=yes
hidecallerid=no
callwaiting=yes
threewaycalling=yes
transfer=yes
echocancel=yes
echocancelwhenbridged=yes
echotraining=yes
echotraining=800 
rxgain=6%
txgain=7%
callerid=asreceived 
;;FXO Modules
Group=1
echocancel=yes
signalling=fxs_ks
context=from-pstn
channel=4