Two wire optical data communication system

Claim 1

A data communication system comprising: (a) a control station including means to request information from a remote station by transmitting a predetermined code over a first single wire, to said remote station, and being operable to receive information transmitted from a remote station over a second single wire; (b) at least one remote station operable to receive a request for information from said control station and for providing said requested information; (c) said remote station including data processing means and a receiving opto-isolator having: (i) an optical transmitter element for receiving and passing an electrical signal transmitted from said control station over said first single wire, for transmitting an optical signal in response to said electrical signal; and (ii) a detector for detecting said optical signal to provide an output signal indicative thereof to said data processing means; (d) said remote station also including a transmitting opto-isolator having: (i) an optical transmitter element for transmitting an optical signal in response to an electrical signal governed by said data processing means; and (ii) a detector for detecting said last named optical signal for allowing electrical signals to be passed by said last named detector; (e) said optical transmitter element of said receiving opto-isolator being connected in series circuit arrangement with said detector of said transmitting opto-isolator such that the electrical signal through said series connected transmitter element is modulated by said detector; (f) said control station including receiver means; and (g) means for providing said modulated signal to said receiver means over said second single wire.