Someone

[trunkgroups]

[channels]
usecallerid=yes
hidecallerid=no
echocancel=yes
echocancelwhenbridged=yes
echotraining=yes
;echotraining=800
relaxdtmf=yes
rxgain=3.0
txgain=0.0
faxdetect=both
musiconhold=default
jitterbuffers=4

context=from-pstn
switchtype=euroisdn
signalling=pri_cpe
pridialplan=unknown
prilocaldialplan=unknown
priindication=inband
resetinterval=never
group=1
channel => 1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,17,18,19,20,21,22,23,24,25,26,27,28,29,30,31