Patent ID: 6021308
Filing Date: 2000-02-01
Classification: H04B,H04H,H04L,H04N

Abstract:
An on-vehicle data communication system comprising at least one master unit, a plurality of slave units and a communication bus for connecting said master unit with said slave units, said system performing a broadcast communication, in which said master unit simultaneously transmits first communication data to all of said slave units, and an ordinary communication, in which said master unit transmits second communication data to specific one of said slave units,each of said slave units comprising:a first receiving means for receiving said first communication data through said communication bus in case of said broadcast communication, and for receiving said second communication data through said communication bus in case of said ordinary communication; anda first transmission means for transmitting first acknowledge data to indicate a failure in reception of said first receiving means if said first receiving means fails to normally receive said first communication data in case of said broadcast communication, and for transmitting second acknowledge data to indicate a success in reception of said first receiving means if said first receiving means normally receives said second communication data in case of said ordinary communication,said master unit comprising:a second transmission means for transmitting said first communication data to all of said slave units in case of broadcast communication, and for transmitting said second communication data to said specific one of said slave units in case of said ordinary communication;a second receiving means for receiving said transmitted first acknowledge data in case of said broadcast communication, and for receiving said transmitted second acknowledge data in case of said ordinary communication; anda process control means for performing a first predetermined process to cope with the failure of said first receiving means if said second receiving means receives said first acknowledge data corresponding to said transmitted first communication data in case of said broadcast communication, and for performing a second predetermined process to cope with a failure of said first receiving means if said second receiving means fails to receive said second acknowledge data corresponding to said transmitted second communication data in case of said ordinary communication.