This standard defines Physical Layer and Medium Access Control specifications for power supply and communication (at 9,600 bps or lower) over power lines from a DC (Direct Current) Power Source (50V or less) to multiple DC loads (more than 10W and less than 2KW for each load and supply capacity more than 100W of one Power transmitter). Each receiver has its own physical address (4 bits or more) and is connected to the transmitter through a pair of power lines (1km or less) in a 1: n multi drop bus or tree topology. The transmitter transmits the DC Power and the electric signals corresponding to the communication packets including the control command/data for controlling the DC loads and the target address through the power line by electrically changing the voltage of the wires. Each receiver supplies power to the DC load with the transmitted and voltage-flattened DC power. Each receiver decodes the control command/data and address from electric signals on the power line and uses them for the connected DC load control if the addresses match. The standard considers compliance to Electro Magnetic Compatibility (EMC) regulations.