DATA COMMUNICATION METHOD FOR CATV SYSTEM

PURPOSE:To compensate the loss including a cable loss or the like due to a temperature change and to improve the stability by measuring a level of a data carrier frequency from a center, comparing the measured level with a prescribed level and varying an incoming carrier level of a response data to the center based on the result of comparison. CONSTITUTION:An outgoing signal sent from the center is given to an amplifier 3 via a branch 2 from a CATV line 1, amplified up to a required level by the amplifier 3 and only the data carrier frequency passes though a band pass filter 4. The level of the data carrier frequency is measured by a level detection section 10 and compared with a preset level by a microprocessor 6. Then a variable attenuator 8 is controlled based on the result of comparison and the incoming carrier level to the amplifier 9 is adjusted. Since the center and a terminal equipment are connected by one coaxial CATV line 1, the loss from the terminal equipment to the center is compensated.