C21Home » Hardware » Modules » C21 XpressNet InterfaceAbstract: Universal XpressNet interface. SpecsXPressNet interfaces on the RTB bus. There can be many of the C21 XPressNet interfaces on the bus.Features,EDG interface (TTL /w signal reshaping)2x XPressNet ports (200mA max)Overcurrent detectionfirmware update over the bus GitHub