===================
zaptel.conf
-----
loadzone = us
deafultzone =us
span=1,1,0,cas,hdb3
cas=1-15:1101
cas=17-31:1101
dchan=16
===================
zapata.conf
-----
[channels]
language=en
usecallerid=yes
hidecallerid=no
callwaiting=yes
usecallingpres=yes
callwaitingcallerid=yes
threewaycalling=yes
transfer=yes
cancallforward=yes
callreturn=yes
echocancel=yes
echocancelwhenbridged=no
rxgain=0.0
txgain=0.0
group=0
callgroup=1
pickupgroup=1
immediate=no
;MFCR2 settings
signalling=mfcr2
mfcr2_variant=ar
mfcr2_get_ani_first=no
mfcr2_max_ani=10
mfcr2_max_dnis=4
mfcr2_category=national_subscriber
mfcr2_logdir=span1
mfcr2_logging=all
mfcr2_call_files=yes
mfcr2_metering_pulse_timeout=-1
context=from-zaptel
group=0
callgroup=0
pickupgroup=0
channel => 1-15,17-31
===================
If you are using a sangoma card you have to use the wancfg utility to set the correct mode (E1, CAS, CRC4 or NON-CRC4, etc).
===================