Fireman's microphone is designed for exclusive use with VM-3000 series. It is equipped with an emergency activation key, permitting pre-recorded evacuation and alert announcements to be activated, and microphone announcements to be made in emergency situations. By connecting RM-320F Fireman's microphone extension to RM-300MF, number of function keys can be expanded. Zone selection or failure acknowledgement function can be assigned to such function keys.