are relationships between the formal IEEE task group and the representative industry alliance-in this case between 802.15 TG4 and the ZigBee Alliance (www.zigbee.org). The ZigBee Alli- ance, formed in October 2002, is a nonprofit industry consortium of companies working together to enable reliable, cost-effective, low-power, wirelessly net- worked monitoring and control products based on an open global standard. The member companies are working together to develop standardized application soft- ware on top of the IEEE 802.15.4 standard. The goal of the ZigBee Alliance is to give consumers the most flexible building systems available by introducing the ZigBee wireless technology into a number of building devices. As of mid-December WPANs 2005, the ZigBee Alliance membership had surpassed 200 member companies from 24 countries spanning six continents, with OEMs and end product manufacturers representing over 30% of the global membership. The ZigBee Alliance focuses on four main areas: defining the network, security, and application software layers of the protocol; providing interoperability and conformance testing for ZigBee devices; promoting the ZigBee brand globally; and managing the evolution of the technology. ZigBee Devices and Networks ZigBee was created to support wireless communications between devices without the expense of having to run wires between them. ZigBee's benefits include flexibil- ity and scalability, reduction in design and installation time, interoperability, longer battery life, and low cost. It is made for two-way communication among devices and can be used to build a general-purpose, inexpensive, self-organizing network of devices. This protocol opens the door to the flexibility and benefits of interoper- ability. Because ZigBee uses open standards, it reduces the costs and risks associ- ated with building the technology into devices. ZigBee is a short-range, low-power protocol specifically designed for small building devices such as thermostats, light- ing controls, ballasts, environment