Control and supervisory signal transmission system

摘要

A parent station output section changes a duty factor between a period in which a control data signal is at a level (high-potential low-level) lower than a power supply voltage Vx but higher than high-level signal in other circuit portions and a subsequent period in which the control data signal is at the power supply voltage Vx level to convert the control data signal into a serial pulse voltage signal and output the voltage signal onto data signal lines D+ and D- in accordance with each data value in the control data signal inputted from a controller in each cycle of a clock.