The MIL-STD-1553B bus is a differential serial bus used in military and aerospace equipment. It is comprised of multiple redundant bus connections and communicates at 1 Mb per second. The serial bus system (Bus Controller (BC), Remote Terminal (RT), and Bus Monitor (BM)) is based on a recently suggested modified implementation of MIL-STD-1553B standard. The Modified MIL-STD-1553B is implemented on an asynchronous RS-485 physical layer. Some modifications were also incorporated to enhance the capability of error detection.The CRC error check is suggested to be added to the Modified MIL-STD-1553B and implemented to improve fault tolerance and error trapping capabilities of the bus. The BC is capable of transmitting commands and receiving responses. It is also capable of errors detection. The RT is capable of receiving commands and transmitting responses and detecting errors. The BM is capable of receiving commands from BC and responses from RTs. Also the BM is capable for tracing, storing, and analyzing the Modified MIL-STD-1553B messages. In addition, the BM displays the analyzed messages on the screen, alerts the user for errors if there is an error, and records them in a text file. The Modified MIL-STD-1553B system is implemented using BC, two RTs, and BM. Various bus terminals were implemented both as a microcontroller based system and as a PC based system. The system proved to be highly robust in terms of fault trapping and resynchronizing after abnormal operation. In addition, the proposed system is a low-cost solution since it uses common serial physical layer hardware rather than specific MIL-STD-1553B hardware.