Network for transmitting and using electromagnetic radiation for two or more functionally different useful purposes. Such a network may be comprised of a signal source apparatus to provide information, an electromagnetic radiation generator capable of being modulated for providing electromagnetic radiation, electronic circuitry for modulating the electromagnetic radiation generator, medium through which the electromagnetic radiation passes and is transmitted, a receiver apparatus for receiving and demodulating the modulated electromagnetic radiation, a first user means for processing and making use of the information to achieve a useful functional purpose, and second user means for achieving a useful functional purpose from said radiation said useful functional purpose being different from the purpose of said first user means.