| 摘要 |
PROBLEM TO BE SOLVED: To provide multi-port polling communication wherein a signal from a terminal is not destroyed at low cost and to reduce trouble in communication. SOLUTION: In a master device (multi-port polling communication module) 1, when a CPU 4 transmits a packet to a driver circuit 50 of each line driver 5 through a serial port 40, the driver circuit 50 transmits the packet to a slave device 2 connected to a port 3. In a line driver 5 selected and controlled by a switch unit and a serial/parallel converting circuit, a receiver circuit 51 receives the packet from the slave device 2 through the port 3 and outputs it to a logic circuit 6. The logic circuit 6 logically adds outputs of the respective receiver circuits 51 together and outputs the addition result to the CPU 4 through the serial port 40. COPYRIGHT: (C)2008,JPO&INPIT
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