tion of an eventual standard, and products built according to the draft specification are expected to become available in 2006. Broadcom has announced the availability of a family of chipsets that it claims are the first prod- ucts designed to comply with the draft. The chipsets, called Intensi-fi, can be used in routers, laptops, and add-in PC cards. There are also proprietary solutions that boost transmission rates to 100Mbps by using MIMO antenna systems. (MIMO is discussed in Chapter 13, "Wireless Communications Basics.") The major vendors of VoWLAN address different classes of user applications, although all focus on several key vertical markets: the mobile workforce, health care, warehousing and distribution, education, and hospitality. The general enter- prise market is considered to be the main market, where the VoWLAN phone could become an adjunct or a replacement for PBX and key system stations. However, general office users are just beginning to embrace WLANs for data, SO voice is likely to be a future phase of those projects. Given the evolving nature of VoWLAN, for the next several years, the primary users are likely to be in specialized applications with a great need for mobility or where wired devices are simply impractical. The Integration of WLANs and Cellular Networks The wireless industry saw a major development in 2004: Avaya (www.avaya.com), Motorola (www.motorola.com), and Proxim (www.proxim.com) announced the first workable solution that allows voice calls to be handed off between WLANs and cellular networks. A similar capability was also developed by Nortel Net- works (www.nortel.com), in partnership with Airespace (now part of Cisco [www. cisco.com]) and SpectraLink (www.spectralink.com). In the recent past, some specialized configurations have integrated wired PBX systems and cellular, but these were the first arrangements to permit voice calls to be handed off from the cellular network to the WLAN and vice versa. The handoff is virtually unnotice- able to the user because it takes less 