[intercom2]
exten => s,1,Set(_FORCE_PAGE=0)
exten => s,n,Macro(user-callerid,)
exten => s,n,GotoIf($[ ${CALLERID(number)} = ${EXTEN:1}]?skipself)
exten => s,n,GotoIf($[ ${FORCE_PAGE} != 1 ]?AVAIL)
exten => s,n,Set(AVAILSTATUS=not checked)
exten => s,n,Goto(SKIPCHECK)
exten => s,n(AVAIL),ChanIsAvail(${DB(DEVICE/${EXTEN:1}/dial)}|js)
exten => s,n(SKIPCHECK),Noop(Seems to be available (state = ${AVAILSTATUS})
exten => s,n,Set(__SIPADDHEADER=Call-Info: \;answer-after=0)
exten => s,n,SIPAddHeader(Call-Info:=\;answer-after=0) ;Linksys
exten => s,n,SIPAddHeader(Alert-Info: Ring Answer) ;Polycom
exten => s,n,Set(__ALERT_INFO=Ring Answer)
exten => s,n,Set(__SIP_URI_OPTIONS=intercom=true)
exten => s,n,Dial(${DB(DEVICE/${EXTEN:1}/dial)},5, A(beep))
exten => s,n(skipself),Noop(Not paging originator)
exten => s,n,Hangup
exten => s,AVAIL+${EXTEN:1},Noop(Channel ${AVAILCHAN} is not available (state = ${AVAILSTATUS}))

exten => _*1XXXX,1,Voicemail(u${EXTEN:1})
exten => _*1XXXX,2,Hangup