Bus amplifier unit Long distance to 480m 1 Extends capacity up to 128 units Fully isolation by optical couplers Repeater/router working mode Up to 2 BDU can be cascaded Specification Power Supply : DC 20 - 28V Power Consumption: Standby 19.3mA(In),47.5mA(Out); Working status : 73.4mA(In),97.2mA(Out); Working temperature: -15ºC - +55ºC; Wiring: 2 wire,non-polarity