A mobile device is not much use unless it can be connected to the information that makes the enterprise run. This connectivity can be as simple as the docking cradle that comes with connected personal organizers. However, mobile real-time data access is available only when you add some form of network connection. Figure 2 illustrates popular options from the inside out, in order of coverage area.
Figure 2 Connectivity options, from the desktop to worldwide.
The docking cradle and infrared port are the most common options for connecting the hand-held to the enterprise. The docking cradle may use a PC serial interface or a USB port. A technology to watch is Bluetooth, which offers similar flexibility to infrared, but without the need for line of sight.
The wireless local area networks (LANs) commonly provide building or campus-wide access (although some business are deploying wireless LANs that cover areas comparable to cellular networks). These networks use unlicensed spectrum, and provide bandwidth comparable to the lower-end wired LANs (for example, several mbits/second and beyond). With the uptake of home wireless LANs, prices have plummeted, which makes a wireless LAN a cost-effective solution for a limited geographic area (for example, a factory floor or company campus). Access requires a wireless LAN card, expansion module, or sled (for example, Xircom's 802.11 sled for the Palm m500). Note that in the last year, wireless LANs have come under attack because of security vulnerabilities. In many cases, wireless LAN deployments were done without the necessary security precautions, and it is possible for unauthorized users to access corporate networks through unsecured wireless access points (this will be discussed further in the next article).
Dial-up access provides connectivity wherever a telephone jack is available. In my experience, this form of connectivity is still the most prevalent method for accessing corporate data while on the move. Because it relies on the public telephone system, virtual private network (VPN) tunneling is usually used for security. Access speeds of 2856Kbps are typical. Although not a truly mobile solution, dial-up access has the advantage of familiarity (users dial up an ISP much like they would at home). Also, dialup access is widely available, being found in most hotels and airports.