[blindxfer_ringback]
; the destination ext should not have vm enabled
exten => _X.,1,NOOP(${BLINDTRANSFER})
exten => _X.,n,set(timeoutd=10) ; set timeout in seconds to dial the transferee
exten => _X.,n,set(extLeng=${LEN(${EXTEN})})
exten => _x.,n,dial(local/${EXTEN}@from-internal,${timeoutd})
exten => _X.,n,Gotoif($["${DIALSTATUS}" = "ANSWER"]?hangup:callback)
; strip the 'SIP/' and ring back
exten => _X.,n(callback),dial(local/${BLINDTRANSFER:4:${extLeng}}@from-internal,,tr)
exten => _X.,n(hangup),hangup()