Xircom unveiled Monday at Comdex a wireless expansion kit for the Handspring Visor, which allows the handheld computer to connect to certain mobile phones. Xircom's SpringPort Wireless Data module supports cellular phones from Ericsson, Nokia and Siemens. Xircom also is working on additional modules supporting Bluetooth and 802.11B wireless networking. Bluetooth-enabled handhelds can communicate to laptops, cell phones or printers without the need of wires, when brought in close proximity. Wireless networking, by contrast, is more specific in function, allowing mobile workers to connect handheld or portable computers to a corporate network or the Internet without the need for wires or cables.