/etc/asterisk/extensions.conf

[salida]
exten => .,1,Answer
exten => .,2,set(calltime=${STRFTIME(${EPOCH},,%C%y-%m-%d--%H\:%M\:%S)})
exten => .,3,MixMonitor(E_${calltime}_from_${CALLERID(num)}to__${EXTEN}.wav)
exten => .,n,Dial(DAHDI/g1/${EXTEN})
exten => h,1,Hangup

[entrada]
exten =>  _XXX,1,Answer
exten =>  _XXX,n,set(calltime=${STRFTIME(${EPOCH},,%C%y-%m-%d--%H\:%M\:%S)})
exten =>  _XXX,n,MixMonitor(E_${calltime}_from_${CALLERID(num)}to__${EXTEN}.wav)
exten =>  _XXX,n,Dial(DAHDI/g2/${EXTEN})
exten => h,1,Hangup