PDA Buyer's Guide - Page 4

Infrared Transceiver Port

In addition to transferring data to your desktop PC through a serial port, many handhelds can communicate with each other through an infrared port. These ports use the same technology as the remote control for your TV or VCR but with a higher data transfer rate (about the same rate as a parallel port). The infrared port on a handheld should conform to the IrDA standard specified by the Infrared Data Association. Any two handhelds running the same operating system, in close proximity, and in a straight line of sight to each other should be able to exchange data through their IrDA ports.

Text Entry & Handwriting Recognition

Only the larger handhelds have actual keyboards, so most handhelds require you to enter information through the touch screen with the stylus. Most systems let you tap letters on an on-screen "keyboard" or write letters on an on-screen tablet. Both Palm OS and Windows CE come with handwriting recognition software--Graffiti and Jot, respectively--that lets you print letters individually. You must form your letters precisely according to the software's rules, which take some time to adjust to.

Other handhelds may come with, or may permit you to buy and install, handwriting recognition software. Instead of following the software's rules for writing letters, you train the software to recognize your own handwriting. The advantage is that you don't have to learn the handheld's writing rules; the disadvantage is that natural handwriting recognition is less accurate, although the accuracy may improve with training.

Power Supply & Batteries

More memory, CompactFlash cards, color screens, voice recording--there are many cool features and accessories for handhelds, but they need battery power to work. Most handhelds come with either alkaline batteries (usually AAA size) or a rechargeable battery pack. Many also include a small backup battery to protect the memory when your main batteries run out.

One set of alkaline batteries usually lasts a few weeks with normal use; rechargeable battery packs typically last several hours between charges. And not by coincidence, the handhelds that come with rechargeable battery packs usually consume more power than those that come with only alkaline batteries. Many handhelds have power-management settings to help the batteries last longer. For example, you can set the backlight or the handheld itself to turn off after a few minutes of idle time.

The most common types of rechargeable battery packs are nickel cadmium (ni-cad), nickel metal hydride (NiMH), and lithium ion. A larger handheld may have a smart battery pack that provides the handheld with information about its power status so that the handheld can conserve power intelligently.

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Note: This buying guide is courtesy of Amazon.com and was written by Mike Brown, a consumer electronics editor for Amazon.com, covering phones, PDAs, printers, scanners, and other products.