cat zapata.conf
[channels]
language=en
context=default
switchtype=national
signalling=fxs_ks
channel => 1-2

cat /etc/zaptel.conf
fxsks=1,2
loadzone = us
defaultzone=us

cat extensions.conf
[globals]
LOCALTRUNK=Zap/1

[default]
exten => 5000,1,Dial(SIP/5000,20)
exten => 5001,1,Dial(SIP/5001,20)
include => outgoing

[outgoing]
ignorepat => 9
exten => _9NXXNXXXXXX,1,Dial(${LOCALTRUNK}/${EXTEN:1})
exten => _9NXXNXXXXXX,2,Playback(invalid)
exten => _9NXXNXXXXXX,3,Hangup