should be checked to ensure that it is sufficient, particularly at aggregation points where data throughput is expected to be high. In extensive installations, with many tens or hundreds of installed devices, maintaining good records of device location and service history will also be important to ensure that the reliability of the network can be efficiently maintained. Current and Future Developments ZigBee is one of the number of competing technologies in the area of sensor networking and remote control. ZigBee's strengths are the IEEE Chapter Ten Table 10-15: Sensor Networking Technologies - Specific Strengths Technology/Alliance Technology strengths and key features Insteon Combination of 132 kHz power line modulation and wireless networking (915 MHz ISM band). Backward compatible with X-10 home automation systems. Dust Networks Full mesh networking - every device has message routing capability. Proprietary 25 channel FHSS radio in the 915 MHz ISM band. Z-Wave Full mesh networking. Proprietary 868/915 MHz ISM band radio (9.6 kbps, BFSK modulation) as well as 802.15.4 compliant products. standard on which it is based and the broad industry alliance which will assure interoperability over a wide product range. Competing sensor networking technologies, such as those offered by Dust Networks, Millennial Net and Insteon are proprietary, although Z-Wave is also backed by an industry alliance and aims to develop IEEE 802.15.4 based products. Each of these proprietary technologies has its own specific advantages, some of which are shown in Table 10-15. Future developments from the ZigBee Alliance could include a ZigBee 2.0 specification based on the enhanced low data rate specification currently under development by the IEEE 802.15 TG4a. This task group is working on an alternate physical layer specification for the 802.15.4 standard which aims to deliver a location capability with an accuracy of 1 metre or better, higher data throughput, ultra-low power and longer range, as well as lower cost. Origins and Main Chara