Polling communication system.

摘要

A communication system containing a master station (10), a plurality of slave stations (201, 202, ... 20n-1, 20n), a transmission line (30, 40) for transmitting a signal between the master station and the plurality of slave stations. The master station contains: a request sending allowance signal sending circuit (35) for sending a request sending allowance signal which addresses one of the plurality of slave stations to give an allowance to send a request for sending data, on transmission line; a request receiving circuit (31) for receiving a request from one of the plurality of slave stations; a request memorizing circuit (34) for memorizing one or more requests from one or more slave stations; and a data sending allowance signal sending circuit (34) for sending a data sending allowance signal which addresses one of the plurality of slave stations to give an allowance to send data, on the transmission line, according to a request which is memorized in the request memorizing circuit. Each of the slave stations comprises: a request sending allowance signal detecting circuit (45) for detecting a request sending allowance signal which addresses its own slave station, on the transmission line; a data sending allowance signal detecting circuit (44) for detecting a data sending allowance signal which addresses its own slave station, on the transmission line; a request sending circuit (45) for sending a request for sending data on the transmission line to the master station when its own slave station detects a request sending allowance signal which addresses its own slave station; and a data sending circuit (44, 43) for sending data on the transmission line to the master station when its own slave station detects a data sending allowance signal which addresses its own slave station.