What is it?

This was mounted in a stairwell in a condo, does anyone know what it is?


fire alarm signal or annunciator

Thank you for your reply, I still dont get it. Is it a sensor? does it sense heat or smoke? What does it do? Sorry, I am ignorant about this.

No, it is not a senser.

It is the audible portion of the alarm system. If you had your ear next to this device when the alarm activates, the screeching noise will ruin your ear drums.

If I’m not mistaken, fire attenuation systems notify the fire department (or alarm companies who are supposed to call the FD) that theres a fire and lets them know the address of it. No one has to be home and the FD gets access from keyboxes at the entry to the condos.
Compared to smoke alarms which lets the occupants (if any) know theres a fire.

Mirtone is now owned by GE. You can contact them, to get more info on this older model annunciator & system, at:
Mirtone USA
8985 Town Center Parkway
Bradenton, FL 34202