WLAN Software Turns PDAs Into Cell Phones
September 18, 2002
Imagine using your PDA instead of your cell phone to make calls -- and not paying anything for the privilege. That's the promise held out by a new 'softphone' produced by TeleSym Inc.
The system, which also works on Microsoft Windows 2000 computers, runs on 802.11 wireless local area networks. That allows phone calls using a mobile device with no cellular charges, as long as the user is in range of a wireless access point.
A number of vendors offer add-ons that turn PDAs into cell phones, and a few companies, including Microsoft, with its Portrait product, offer voice over IP (VoIP) products similar to the SymPhone.
TeleSym says that its software technology eliminates delays, by setting the priority of voice packets on the network higher than that of data transmissions, and produces very high-quality sound.
"The voice quality is extremely good," says Zackary O'Donnell, a wireless development analyst at the University of California at Davis.
Voice and Data on One Device
UC Davis has been investigating the SymPhone, with the vision of a future campus-wide voice network in mind."We think that mobile computing over wireless devices will the computing method of choice for students in the future," says O'Donnell. With software like SymPhone, he says, "Students could call each other on campus, and faculty could use it to call their office, or call for audiovisual support in a classroom."
The university is still experimenting to see how voice traffic might affect its network, and how many people a single wireless access point might be able to support.
TeleSym is mainly aiming SymPhone at companies with mobile workers. According to Raju Gulabani, the company's president and CEO, the technology could be useful in places where workers need to move around, like a retail store. If a customer calls a clothing store looking for a particular sweater, a clerk could check the shelves, and then use the PDA to check inventory at the warehouse or other stores, all the while talking to the customer.
"You can increase the return on investment of your wireless LAN," says Gulabani. "It makes it easier on workers, who can now get voice and data without having to carry multiple devices."
Wireless LANs, however, have a limited range, so employees who travel outside company offices will probably still have to carry a cell phone. They can still save on airtime charges, says Joe Dodson, TeleSym's vice president of marketing, by taking calls on the PDA where a wireless LAN is available. While still relatively few in number, public access points in places like airports, hotels and convention centers are growing steadily.
What's more, simply setting calls to forward from the PDA to the cell phone makes the transition transparent to the user, says Dodson.
"If you're in range of a wireless local area network," he says, "you can take the call on your PDA using VoIP, at no charge. If you're out of range, you can answer the call on your cell phone."
SymPhone is sold through distributors; suggested pricing is about $300 per user.