ABSTRACTThe Shipboard Data Multiplex System (SDMS) is a general purpose information transfer system directed toward fulfilling the internal data Intercommunication requirements of a variety of naval combatant ships and submarines in the 1980–1990 time frame. The need for a modern data transfer system of the size and capability of SDMS has been increase in unison with the sophistication of shipboard electronic equipment and the associated magnitude of equipment‐to‐equipment signal traffic.Instead of the miles of unique cabling that must be specifically designed for each ship, SDMS will meet information transfer needs with general‐purpose multiplex cable that will be Installed according to a standard plan that does not vary with changes to the ship's electronics suite. Perhaps the greatest impact of SDMS will be the decoupling of ship subsystems from each other and from the ship. Standard multiplex interfaces will avoid the cost and delay of modifying subsystems to make them compatible. The ability to wire a new ship according to a standard multiplex cable plan, long before the ship subsystems are fully defined, frees both the ship and the subsystems to develop at their own pace, will allow compression of the development schedules and will provide ships with more advanced subsystems.This paper describes the SDMS system currently being developed by the U.S. Navy.