exten => _9[2-9].,1,Set(CALLERID(name)=mycompanyname)
exten => _9[2-9].,2,Set(CALLERID(num)=8005551212)
exten => _9[2-9].,3,ChanIsAvail(${TRUNK})
exten => _9[2-9].,4,Dial(${TRUNK}/423${EXTEN:1},60,r)
exten => _9[2-9].,5,HangUp
exten => _9[2-9].,104,Playback(tt-allbusy)
exten => _9[2-9].,105,Hangup