/etc/zaptel.conf

loadzone=de
defaultzone=de
span=1,1,0,ccs,hdb3,crc4
bchan=1-15
dchan=16
bchan=17-31

/etc/asterisk/zapata.conf

[trunkgroups]
spanmap => 1,1,1
[channels]
switchtype=national
language=de
context=roitel
signalling=pri_cpe
usecallerid=yes
hidecallerid=no
callwaiting=yes
usecallingpres=yes
callwaitingcallerid=yes
threewaycalling=yes
transfer=yes
canpark=yes
cancallforward=yes
callreturn=yes
echocancel=yes
echocancelwhenbridged=yes
rxgain=0.0
txgain=0.0
immediate=no
group=1
callgroup=1
dchannel=>16
channel=>1-15,17-31