SAE AS4074A

This standard specifies the characteristics of the SAE Linear Token Passing Bus (LTPB) Interface Unit.The LTPB provides a high reliability, high bandwidth, low latency serial interconnection network suitable for utilization in real time military and commercial applications. Multiple redundant data paths can be implemented to enhance reliability and survivability in those applications which require these attributes. The token passing and data exchange protocols are optimized to provide low latency and fast failure detection and correction. Physical configurations with bus lengths up to 1000 m can be accommodated.This specification defines the following:aGeneral Description (3.1): An overview of the LTPB protocol.bPhysical Media Interface (3.2): This portion of the standard defines the physical interface to both optical and electrical bus media.cAccess Protocol Definition (3.3): This portion of the standard defines the symbols, frame formats, timing functions and traffic recording requirements of the Token Passing Interface Unit (TPIU).dNetwork Protocol Definition (3.4): This portion of the standard defines the network control and station management functions.eTest and Verification (Section 4): This paragraph defines the responsibilities and methods for test and verification of the LTPB.fTPIU State Machine (Section 5): This section defines the TPIU States and state transition rules.