/etc/asterisk/zapata.conf
[trunkgroups]

trunkgroup=>1,24
spanmap => 1,1,0
spanmap => 2,1,2
spanmap => 3,1,3
spanmap => 4,1,4

[channels]

language=en
context=from-pstn
group=1
signalling=pri_cpe
switchtype=5ess
callerid=asreceived under
rxwink=300
usecallerid=yes
hidecallerid=no
callwaiting=yes
usecallingpres=yes
callwaitingcallerid=yes
threewaycalling=yes
transfer=yes
cancallforward=yes
callreturn=yes
echocancel=yes
echocancelwhenbridged=yes
echotraining=400
rxgain=0.0
txgain=0.0
callgroup=1
pickupgroup=1
immediate=no
channel => 1-23,25-48,49-72,73-96

/etc/zaptel.conf

span=1,1,0,esf,b8zs
span=2,2,0,esf,b8zs
span=3,3,0,esf,b8zs
span=4,4,0,esf,b8zs
bchan=1-23,25-48,49-72,73-96
dchan=24
loadzone = us
defaultzone = us