Abstract: In a data processing system of the type having multiple processor units coupled to one another by a bus means for interprocessor communications there is provided a fiber optic interconnection system to interconnect the bus means of multiple processor sections to one another, thereby allowing groups of the processor units to be physically spaced from one another. The fiber optic interconnect system includes, for each multiprocessor unit section functions to receive messages communicated on the interprocessor bus of that section for receipt by a destination processor of the other section, format the message for fiber optic transmission, and transmit the message; and circuitry for receiving messages on the fiber optic link, scheduling the message for transmission to the destination processor, and maintaining that scheduling in the face of receipt of another message for the same processor unit.