The 1553B BUS is short for MIL-STD-1553 bus, where B is bus. MIL-STD-1553 bus is the time-divided command/response multiplexing data bus inside the aircraft. 1553B data bus standard is a serial multiplex data bus standard published by the United States in the 1970s. 1553B bus can be hung 31 remote terminals, 1553B bus adopts command/response communication protocol, it has three terminal types: bus controller (BC), remote terminal (RT) and bus monitor (BM); The information formats include BC to RT, RT to BC, RT to RT, broadcast mode and system control mode. The transmission medium is shielded twisted pair wire, 1553B bus coupling mode has direct coupling and transformer coupling; The 1553B bus is a multi-redundant bus topology with bi-directional transmission characteristics. Its transmission speed is 1Mbps and the transmission mode is half duplex. Manchester code is adopted for encoding transmission. This coding method is suitable for transformer coupling. Because direct coupling is not conducive to terminal fault isolation, the whole bus network will be completely paralyzed because of a terminal fault, so it is clearly indicated in the protocol that direct coupling is not recommended.