The Guardian Alert lets residents receive wireless messages

TheGuardian Alert is used to wirelessly send emergency or non emergency messagesto residents. An emergency message emits a loud tone and flashes a red light,followed by the message display on the LCD screen. Then the message isconverted to an audible voice message. Non-emergency messages can be deliveredwithout the audible and visual alerting. No wiring is needed, just a standardelectrical outlet for power.

http://www.guardianalert.com/