COMMUNICATION DEVICE WITH POWER SUPPLY POWER FEEDING TYPE COMMUNICATION LINE

摘要

PROBLEM TO BE SOLVED: To provide a communication device with a power supply power feeding type communication line with a simple configuration and excellent performance. SOLUTION: A master controller 1 supplies power to slave controller 4, 5 through communication lines 2, 3 by means of a 1st level. The master controller 1 and the slave controller 4, 5 make digital communication in an ordinary communication mode by using 1st and 2nd levels for the communication line levels. Furthermore, the master controller 1 forcibly causes the level of the communication line 2 to be changed from the level or the 2nd level to a 3rd level so as to make emergent transmission to the slave controller 4 or 5.