Abstract: A single optical fiber having a core with at least one planar side is arranged in an open loop configuration to form a bus which is run between a plurality of communications stations to be served. The legs of the loop are placed side by side to form a paired line cable which interconnects the stations. At each station, a transmit line is coupled into one of the cable lines, and a receive line coupled into the other, such coupling being achieved without breaking the fiber core, by means of a coupler such as a prism, taper, grating coupler or the like, which abuts against an exposed planar portion of the fiber core. Electrical signals are modulated onto a light beam generated at each station by means of a photo-emitter, the light signals received at each station being demodulated from the light beam and processed for utilization as may be required. A multiplex control is employed to time multiplex the signals transmitted from the various stations.