Simultaneous Bi-directional Digital Data Transfer Over A Single Transmission Line

Reference#: P02075

Telephone systems have used “two-to-four-wire hybrids” for years. A telephone hybrid is a multi-winding transformer that connects the two wires of the receiver and the two wires of the transmitter to a single wire pair. It allows cancellation of the local voice signal so that the distant signal may be heard more clearly.

The Johns Hopkins Applied Physics Laboratory has restructured the method for transmitting digital information between two nodes simultaneously in both directions (full-duplex) by using only a single transmission line and without modems or other signal modulation devices. This method applies to binary (two-level) signaling, as used in digital systems. The number of wires is reduced by a factor of two by simply adding six resistors to each end. This method makes use of standard digital data transmission components and no additional active components are required. It may also use a twisted pair as the transmission line, but other types may be used with adaptation. This technology is ready to license as a final product and would benefit companies with any digital communication systems that use full-duplex (simultaneous bi-directional) transmission.

*Available for licensing opportunities

Dr. G. R. Jacobovitz
Phone: (443) 778-9899