 times per second in a pseudo- random pattern. Connected Bluetooth devices are grouped into networks called piconets; each piconet contains one master and up to seven active slaves. The channel- hopping sequence of each piconet is derived from the master's clock. All the slave devices must remain synchronized with that clock. FEC is used on all packet head- ers, by transmitting each bit in the header three times. The Hamming Code is also used for FEC of the data payload of some packet types. The Hamming Code intro- duces a 50% overhead on each data packet but is able to correct all single-bit errors WPANs and detect all double-bit errors in each 15-bit codeword (each 15-bit codeword contains 10 bits of information). Bluetooth wireless technology is set to revolutionize the personal connectivity market by providing freedom from wired connections for portable handheld devices. The Bluetooth SIG is driving development of the technology and bringing it to market. The IEEE Bluetooth standard gives the Bluetooth SIG's specification greater validity and support in the market and is an additional resource for those who implement Bluetooth devices. This collaboration is a good example of how a standards development organization and a special interest group can work together to improve an industry specification and also create a standard. As of May 2005, 5 million Bluetooth units were shipping per week, demon- strating the wide acceptance of Bluetooth technology in a multitude of applica- tions, such as mobile phones, cars, portable computers, MP3 players, mouse devices, and keyboards. New applications are routinely introduced. For example, one new application involves the digital music kiosks found in thousands of retail locations. These kiosks are beginning to appear with Bluetooth wireless technology, allowing songs to be transferred directly to music-capable mobile phones. Bluetooth wireless technology is the leading short-range wireless technology on the market today. It is now available in its fourth version of the c