| 摘要 |
PURPOSE:To obtain a utilization factor of a transmission line which is equal to dynamic assignment without changing a transmission control procedure, etc., and to shorten remarkably an ineffective time by adding a simple constitution for providing a signal detecting means and a timer part on a master station. CONSTITUTION:A control part 70 sends out contents of an address counter 54 to a transmission line 40 from a driver 50 through a transmitting circuit 52 in order to send out a mark to each station. As a result, the mark to the slave station corresponding to the address counter 54 is sent out from the transmitting circuit 52. The corresponding slave station which has received the mark sends out a transmitting data in case when the transmitting data exists, and executes no response in case when said data does not exists. A timer 56 is started from when the mark is sent out. After the mark is sent out, a signal detecting part 62 monitors through a receiver 60 whether the data is sent out to the transmission line 40 from the slave station or not. When a signal detecting part 62 detects a fact that the data is sent out onto the transmission line, a detecting signal 72 is sent to a transmission discriminating part 64, and also the data on the transmission line is stored in a receiving buffer 68 through a receiving circuit 66. |
