LIGHTING LINE CARRIER COMMUNICATION EQUIPMENT

PROBLEM TO BE SOLVED: To maintain voltage at transmission/reception ends of the communication equipment as high and to continue good communication even when impedance of a lighting line is varied. SOLUTION: An impedance varying means 102 is connected between the communication equipment 100 and the lighting line L. The impedance ZL of the lighting line is measured before starting the communication by an impedance measurement means 103. Variable impedance of the impedance varying means 102 is adjusted from the measured impedance so that the voltage VS at the transmission/reception ends becomes the maximum by an impedance adjustment means 104. Consequently, the communication is performed with large amount of the voltage at the transmission/reception ends even when an electric equipment is connected with the lighting line L1 and the impedance of the lighting line L1 is lowered.