COMMUNICATION SYSTEM, COMMUNICATION DEVICE, AND COMMUNICATION METHOD USED FOR THEM

PROBLEM TO BE SOLVED: To provide a communication system that prevents data from being erased easily even if a transmission line band is reduced, and copes with a change in the band. SOLUTION: In the communication system for performing communication between communication devices by the transmission line of which the communication band changes, a plurality of lines are divided into a plurality of multiplexing groups according to the priority of the data. A communication device 1 includes: a detection means 11 for detecting an increase/decrease in the communication band of the transmission line 100; and blocking means 12-1 to 12-m, 13-1 to 13-n for blocking or releasing a line belonging to each of the plurality of multiplexing groups according to a result detected by the detection means. COPYRIGHT: (C)2010,JPO&INPIT