scope:

This specification contains definitions and requirements for the various functional components which together constitute the Version C ASCB. The Version C ASCB, as defined, is a complete bus network subsystem composed of redundant interconnect, control, and user interface functions. In addition to basic structure, bus protocol, and timing requirements, this document defines the safety and redundancy aspects of the ASCB. The definition presented supports Critical and Essential communications requirements of integrated avionics systems composed of dual, triplex, or quad redundant bus user subsystems.

This specification defines in detail the requirements that must be met within any subsystem connected to the ASCB, within the bus controller, and the interconnect structure, to help ensure that bus sub-system safety and availability goals can be met. In many areas, this specification goes beyond the specification of requirements, and actually specifies a design approach that is intended to meet the availability and data integrity requirements.

This specification also presents installation requirements which are designed to meet the EMI and lightning susceptibility, and EMI emissions requirements of DO-160(C or later). Finally, the actual definitions of data field contents and sequencing order for the Version C user subsystems are presented in Sections 7 and 8 of this specification.