Extensions.conf

[default]
;
; By default we include the demo.  In a production system, you
; probably don't want to have the demo there.
;
;exten => 3510041,1,Dial(Zap/1/${EXTEN})
exten => _1512XXXXXX,1,Dial,Zap/g2/${EXTEN}
exten => 15123510041,1,Dial(Zap/1/${EXTEN})

/etc/asterisk/zapata.conf:
signalling=fxo_ks ; FXS for ringing phones
echocancel=yes ; You can set this to 32, 64, or 128, tweak to your needs.
echocancelwhenbridged=yes
echotraining=400 ; Asterisk trains to the beginning of the call, number is in milliseconds
callerid=asreceived
group=1
context=default ; Points to the default context of your extensions.conf
channel => 25-48

signalling=fxo_ks ; FXO for connecting to the Telco
group=2
context=incoming
channel=> 1-24 ; Change 24 to 31 for E1


/etc/zapata.conf

span=1,0,0,d4,ami
span=2,0,0,d4,ami

fxoks=1-48

loadzone = us
defaultzone=us