application intrusion fire fume detection active vigilance music and intercom but with the present invention it is possible to do so the novelty of the present invention is its ability to adapt to any or all of the stated applications and those not yet defined it is obvious that the present invention may be used as a single installation or as a plurality of such installations within a building or set of offices etc it is well known to interconnect smoke alarm devices wirelessly so that when one smoke alarm is activated all of the units within the communications network are also activated so as to alert persons that are not near the initial detector likewise plural units of the present invention may be linked in the same way so as to alert all occupants of intrusion fire or fume detection and to provide for overall vigilance music and intercom it is well known to provide such networks of sensors in a building especially for fire and security uses in like manner the present invention may be used in networks to advantage by wireless and wired connections in fig3 we show that components or units of the present invention may be provided with antennas for communication with other components or units wirelessly although much of the technology of the present invention is well known in the art the novelty of the present invention lies with the facilitation of mounting components near the rim of a recessed lighting fixture with the possibility of placement of components at a desired position by selecting a knockout to place the component with a field of view in a selected direction the invention also provides a plurality of power outlets 20 for providing power to a selection of.