A receiver system (100) having at least one receiver(101)for receiving optical communications signals(103b)that encode or transmit information; wherein the receiver system (100) is adapted to produce one or more electrical signals(104)from the received optical signal(103b)and/or from ambient light(103a)such that the receiver system (100) is usable as a source of electrical power and the encoded or transmitted information from the received optical communication signal(103b)is recovered or recoverable from the electrical signal(s)(104). Embodiments of the invention also relate to a communications system(400)that further comprises one or more transmitters(406)and a device having the receiver systems(401), along with associated methods of using and producing. Particular embodiments relate to identification tags(1000)and user devices(300)having a display(301)that at least partially overlaps the receiver(s)(302).