reduced function device (WirelessUSB, ZigBee) (RFD)
In radio networks according to IEEE 802.15.4, in ZigBee and Wireless Sensor Networks(WSN), there are three functional network nodes: The PAN coordinator, stations with router functionality, which are the Full Function Devices( FFD), and ZigBee terminals with reduced functionality, the Reduced Function Devices (RFD).
RFD nodes are end nodes with limited functionality, extremely simple implementation and reduced protocol set. Moreover, they can communicate only with FFD nodes or with PAN coordinators. Typical RFD stations are sensors and actuators that are interrogated by the FFD nodes or perform a simple control function. RFD stations include switches and actuators and sensors. Since RFD nodes rarely become active, they are in an energy-saving sleep mode most of the time.