What is the use of AUTODIALER in FACP and how its work?

It is a interface device between FIRE ALARM MAIN CONTROL PANEL AND CIVIL DEFENSE SERVER.  It help to ring out and give message during fire triggering mode to optional numbering system. It has to be connected via IFU or TR [ Transponder ] by NO / NC volt free contact. Also telephonic land line to be connected with AUTODIALER UNIT. 

It is very useful to reach fire alarm mode to concern technical team instantly and to reach civil fire service to the spot.