While communicating with

摘要

PROBLEM TO BE SOLVED: To secure reliability in communication without receiving a response signal from the destination of transmission even in the case of simultaneous transmission to many terminal control parts by broadcasting. ;SOLUTION: A main control part 1 has a function for transmitting a broadcasting command to plural terminal control parts and the terminal control part switches the input/output of a control line 11 when the broadcasting command is received, and outputs the same level signal as input to the side of output. When there is a communication error in the received broadcasting command, the output of the control line is inverted to a low(L) level. After the broadcasting command is transmitted, the main control part 1 switches the control line 11 to an input mode, recognizes the presence of the communication error from the inversion of the level of the control line to L and sends the broadcasting command again.;COPYRIGHT: (C)2000,JPO