The Siemens – Fire Safety Intelligent Remote Lamps (Models ILED-XC | ILED-XW) are specifically tailored for use with initiating devices that are concealed or otherwise not easily within view (e.g. – above suspended ceilings; under sub-floors, in unexposed ventilating ducts, normally locked vaults or closed rooms, etc.) The Intelligent Remote Alarm Lamps can connect to Siemens addressable fire-alarm control panels (FACPs). Model ILED-XC is mounted on a 4-inch (10.2 cm.) octagon outlet box. Model ILED-XW is fastened on a single-gang electrical box. The module uses one (1) address on the loop.