The RM-320F Fireman's Microphone is designed for exclusive use with the 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 the RM-320F Fireman's Microphone Extension to the RM-300MF, the number of function keys can be expanded. The zone selection or failure acknowledgement function can be assigned to such function keys.