ooth, HomeRF and IEEE 802.11 are the main contenders. Each of these has its own advantages and is aimed at a slightly different market. Bluetooth technology is aimed at providing short range, often ad hoc connections between units. It is designed SO that it can be designed into an application specific IC (ASIC) to reduce its cost and also keep its size down. It is also aimed at the cellular telecommunications market where it is expected to be included in cellular phones SO that they can easily connect to items such as laptop computers. The HomeRF technology, as the name indicates, is aimed very much towards applications in the home. It will be able to provide connectivity for multiple computers in the home onto a single Internet access point, generally computer interconnectivity, and many other applications. Its main features are its simplicity, low cost and its scalability, enabling voice also to be carried over it. Finally there is IEEE specification 802.11. This is aimed very much at the business market where performance is the key factor. It is being incorporated into many laptop computers to provide features such as roaming, while also giving a high degree of security. The different technologies share many things in common, although they are not able to interface with one another. One of the major common aspects is that they all work in the industrial, scientific, and medical portions of the spectrum for which no licence is required. The main band that is used is the 2.4 GHz band. The others are 915 MHz and 5 GHz. As these bands do not require a licence, and they have many users, even microwave ovens use frequencies in the band. Accordingly, all three systems have methods of being able to avoid the high levels of interference that are to be found there. Short-range wireless data communications 283 Bluetooth This technology traces its origins back to 1998 when a special interest group was formed by IBM, Intel, Nokia and Toshiba. The name of the standard originates from the Danish king Harald Blatand who was r