Abstract: An IR FM communication system for full-duplex communication between mobile IR devices such as headsets or a headset and a module that is connectable to an aircraft or other vehicle communication system. Each mobile IR device includes a transmitter circuit and a receiver circuit. The transmitter produces an IR emission beam extending approximately 360° in azimuth and at least 15° in elevation. The receiver has a detection envelope extending approximately 360° in azimuth and at least 45° in elevation.

Abstract: A hydraulically operated handler for drums and the like is mounted on the boom of a tractor so as to be selectively pivoted from a vertical position to fifteen degrees past a horizontal position. Grappling arms are mounted on a front plate which is selectively rotatable through 360.degree. by a hydraulic motor. A spindle rotatably supporting the front plate contains hydraulic operating fluid passages which are coupled through a rotating coupling mechanism to hydraulic cylinders operating the grappling arms. The selective pivotal motion together with the ability to selectively rotate the grappling hooks 360.degree. enables effective gripping and handling of drums.