Public Address.

You can shout! although it is far more effective to use a public address system to get your message across.

Forget all those dodgy radios that staff want to bring in (which probably cause issues alone) and use the P.A system to pipe music throughout the workplace*, which shuts off when mesages are announced.

These can also be installed in external locations to warn off potential intruders, or to assist in evacuation situations.

Performing rights license may be required in certain installations*.