[root@rlscallmon01 ~]# cat my_zaptel.conf
fxols=1-2
fxsls=3-4
loadzone = us
defaultzone=us
[root@rlscallmon01 ~]# cat my_zapata.conf 
[trunkgroups]

[channels]
usecallerid=yes
hidecallerid=no
callwaiting=no
threewaycalling=yes
transfer=yes
echocancel=yes
echotraining=yes
immediate=no

context=incoming
signalling=fxs_ls
channel => 3
[root@rlscallmon01 ~]# ztcfg -vvv

Zaptel Version: 1.4.1
Echo Canceller: MG2
Configuration
======================


Channel map:

Channel 01: FXO Loopstart (Default) (Slaves: 01)
Channel 02: FXO Loopstart (Default) (Slaves: 02)
Channel 03: FXS Loopstart (Default) (Slaves: 03)
Channel 04: FXS Loopstart (Default) (Slaves: 04)

4 channels configured.

[root@rlscallmon01 ~]#