MIL-STD-1773

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                   MIL-STD-1773, MILITARY STANDARD: FIBER OPTICS MECHANIZATION OF AN AIRCRAFT INTERNAL TIME DIVISION COMMAND/RESPONSE MULTIPLEX DATA BUS (20 MAY 1988).,  This standard defines requirements for digital, command/response time division multiplexing (data bus) techniques on aircraft. It encompasses the fiber optic data bus transmission line, the electro-optical transmission and reception units, and the associated interface electronics. The concept of operation and information flow on the multiplex data bus and the optical, electrical and functional formats to be employed are also defined. When invoked in a specification or statement-of-work, these requirements shall apply to the multiplex data bus and associated equipment which is developed either alone or as a portion of an aircraft weapon system or subsystem development. The contractor is responsible for invoking all of the applicable requirements of this Military Standard on any and all subcontractors he may employ. Potential Air Force users of MIL-STD-1773 should consider the following: a. The Air Force is presently using the wire data bus covered by MIL-STD-1553 for 1-MHz transmission. b. At this time, Air Force standardization in the use of a fiber optics bus for the same 1-MHz transmission would not reduce cost or increase interoperability, interchangeability, reliability, or the other benefits associated with standardization in general. c. The Air Force intends to pursue fiber optics application for a standardized avionics high speed data bus to take advantage of the inherent wide bandwidth characteristics of the fiber. The purpose of this standard is twofold: (a) it seeks to preserve the multiplex bus techniques which have been standardized in MIL-STD-1553, and (b) it provides guidelines for the application of fiber optic transmission techniques to the MIL-STD-1553 interconnect. Use of this standard alone will not ensure total compatibility of transmission characteristics between different systems which employ a fiber optic interconnect; however, it will ensure general compatibility of the optical modulation techniques. The optical power levels, optical wavelength and the means for distributing optical power in any specific implementation must be contained in a specification which references this standard.