zaptel.conf:

fxoks=1
fxsks=4

zapata.conf:

echocancel=yes
echocancelwhenbridged=yes
echotraining=400
colerid=asreceived
signalling=fxs_ks
context=incoming
chanel=>1

signalling=fxo_ks
callerid="Test Phone"
context=default
channel=>4


extensions.conf:

exten => 1000,1,Dial,Zap/1|20
exten => 1000,2,Voicemail,u1000
exten => 1000,3,Hangup
exten => 1000,102,Voicemail,b1000
exten => 1000,103,Hangup


exten => _9NXXXXXX,1,Dial(Zap/2/${EXTEN:1}|20,t)

[incoming]
exten => s,1,Wait(1)
exten => s,2,Dial(Zap/2|20,t)
exten => s,3,Voicemail,u9000
exten => s,4,Hangup
exten => s,103,Voicemail,b9000
exten => s,104,Hangup