A multipurpose ceiling fixture selectively receives and powers multiple components. A mounting strap supports a lamp socket, a battery socket, and plural power outlets for selected components. A cylindrical lamp housing within the fixture is attached to the mounting strap and a lamp is engaged with the lamp socket. An annular mounting chassis is adapted for receiving a plurality of the components which may include a loudspeaker; detectors of particles, heat, motion, sound and noxious gas; an audible alarm; a video cam; and an intercom. One may select only those components that are of interest to a particular installation and then can install such components into power sockets and on one or another of the several mounting surfaces. Of particular advantage is a mounting chassis that allows components a line of sight lateral to the fixture.