Microsoft supports three separate mobile OSs, all based on Windows CE. Its pure PDA OS is Pocket PC 2003, on which many vendors support wireless data services, with some even supporting voice. Manufacturers trying to optimize for the phone market while preserving full PDA capabilities often rely on Pocket PC Phone Edition. Meantime, Microsoft is pitching the Windows Mobile-based Smartphone, an OS designed for mobile phones, to phone makers like Motorola and Samsung.
The platform with the broadest base of app support is PalmOS. But there are two major variations of it--PalmOS 4 and PalmOS 5--and some subtle application-compatibility issues between the two. In addition to licensing its OS to Kyocera, Samsung and others, Palm offers its own smart phone, the Treo, through its palmOne division.
It's worth noting Research In Motion's role in this market. Blackberry devices are based on RIM's proprietary OS platform, which has been optimized for mobile e-mail services. Newer RIM devices also support cellular voice and data. RIM has done an excellent job delivering enterprise-class messaging and management, but support from third-party developers is limited.
Although PDAs often are used with PC cradles or hardwired network interfaces, the clear trend is toward enabling these devices for wireless services, with an add-on network interface card (PC Card, Compact Flash or SD/IO) or embedded interfaces. If the goal is to support voice and data, you usually need to support Wi-Fi WLAN standards (mostly 11b for now, but 11a and 11g in the future) and evolving cellular-data standards. In addition, Bluetooth plays a key role in this market.
Most devices based on Pocket PC provide effective Wi-Fi support, and many include embedded 802.11b NICs. The news is not good for PalmOS users: Only a limited number of Palm devices include integrated Wi-Fi support. In addition, while SD/IO Wi-Fi NICs are available from SanDisk and plamOne, these interfaces are not supported on all PalmOS devices that support SD/IO. Finally, though the Symbian OS can support Wi-Fi, devices with integrated WLAN services, like the Nokia Communicator 9500, are just beginning to emerge.
