ABSTRACT
Avionics Standard Communication Bus (ASCB) is a proprietary communication protocol for the avionics domain of general, business, and regional aviation aircraft. The general aviation market comprises small multiple-seater aircraft, the business aviation market consists of turbo-engine-powered comfortable small aircraft for business clients, and regional aviation aircraft are single-aisle medium-sized aircraft flying regionally with up to about 100 passengers. Honeywell has developed ASCB for fault-tolerant periodic, real-time communication between avionic modules of its Primus Epic avionics suit deployed in such aircraft. ASCB is the primary bus in Primus Epic. There are multiple ASCB versions available, some standardized, the latest being version D, abbreviated as ASCB-D. ASCB-D is based on an architecture consisting of four Ethernet buses, two for each side of an airplane. Clock synchronization, start-up, or reintegration in Primus Epic is basically the same, as ASCB deploys a master-selection protocol between four cooperating masters called time servers.
