A ZigBee terminal device, such as a sensor, that can perform only a single monitoring or control function. A ZED comprises a low-cost microprocessor, RAM and ROM, a long-life battery, and a low-power radio and controller. A ZED is small enough to be embedded in a light switch, smoke or carbon dioxide detector, thermostat, security sensor, utility meter, or medical sensor. A ZED can communication only with a ZigBee Router (ZR), and not other ZEDs. See also ZigBee and ZR.