Four or five years ago, ZigBee had a burst of publicity. Why has it gone quiet since then? ZigBee promised to integrate wireless sensors - light switches, burglar alarms and just about everything else - into mesh networks, using economical low-power, low-speed connections. Using links defined by IEEE 802.15.4, it promised networked devices with a battery life of five or ten years, that could be installed and left to run. But what's happened? We've yet to see any ZigBee installations, and we keep hearing of competitors, including proprietary technology like Z-Wave's Zensys, new systems that use IP over 802.15.4, and...