The grasp communication makes use of voltage signaling, the place 1 (idle state, mark) is the bus nominal 36 volts, zero (area) drops the voltage to 24 volts (V). M-Bus uses two-wire phone cable (JYStY 1x2x0.Eight mm or similar, 73 ohm/km, 120 nF/km) most size of 350 meters when utilizing nominal transfer speeds 300 and 9600 baud.