Both UPS's DIAD V and FedEx's Star IV/PowerPad handheld computers incorporate Gobi radio technology. Manufactured by Qualcomm, the technology allows a single device to communicate over both Code Division Multiple Access (CDMA) and General Packet Radio Service (GPRS) networks.

Here's how it works: Companies that are using computers in conjunction with Gobi-enabled radios can develop algorithms to evaluate the device's activity on the wireless network, considering factors such as signal strength and data-throughput speeds, said Greg Payne, senior manager, mobility systems at Honeywell Scanning and Mobility of Fort Mill, S.C., which makes UPS's DIAD V. If performance on the GPRS network, for example, drops below a certain threshold, the device would power off the GPRS radio and then try to connect to a CDMA network.

"That all happens behind the scenes, so the user would never know that it's jumping from one network to the other," Payne said.

UPS used to give each driver a DIAD containing either a GPRS or CDMA radio, depending on the coverage in the driver's area, said Todd Brown, project manager at UPS. "If you needed a different radio, you would have to send the unit back to get a different radio put in, or we would send you a different terminal." The Gobi radio has eliminated the need for those kinds of changes.

Most of FedEx Ground's data traffic to and from the field travels over AT&T's GPRS network, said Ken Spangler, the business unit's senior vice president of information technology and chief information officer. But the Gobi provides other options in areas where AT&T's coverage isn't sufficient. "We put [the radio] on whatever network is appropriate," Spangler said.

Read the main story, "Tracking the evolution of package tracking" to learn how UPS and FedEx tracking capabilties have developed.