PDA Buyer's Guide: What to look for when buying a handheld

Size
As handhelds have evolved, their overall size hasn't changed dramatically. Most current models are between 100 and 150mm long and about 50 to 80mm wide, and they weigh between 100 and 200 grams. Examples of extremely compact PDAs are the HP iPaq rw6828 and Palm Z22, while on the other side of the spectrum, you'll find handhelds like the Dopod P800W. Ideally, they should ride comfortably in a coat pocket or a purse and have a screen large enough for on-the-go viewing. To determine if the size and shape of a particular PDA works for you, take a trip to your local retailer, as you can't know for sure based on the published specs. You'll want to see how it feels in your hands -- light or heavy, sturdy or fragile -- and if you're comfortable with the button layout for one-handed navigation.

Display
Colour displays are the norm for handhelds these days. They are easier on the eyes, and are necessary because of all the multimedia features present on PDAs like image viewing and video playback.

Pay attention to screen resolution; All Windows Mobile handhelds will have at least 240 x 240-pixel resolution. You can still find Palm devices with 160 x 160 resolution, but our recommendation is to opt for a model with at least 320 x 320 pixels. Regardless of which OS you choose, selecting a model with higher resolution shows off images to their best effect. Some of the devices even come with VGA displays, but these handhelds tend to be larger in size.

Another consideration is the screen's performance in sunlight. The first colour screens were practically illegible outdoors, but newer liquid-crystal displays (LCDs) have solved the problem. In particular, transflective thin-film transistor (TFT) screens are one of the best performers indoors and out, due to their reflective properties, which cause sunlight to bounce off the screen. For indoor use, a backlight provides illumination indoors or in the dark but drains battery life.

Memory
Not so long ago, PDAs typically had their operating system stored in ROM (read-only memory) and use built-in RAM (random access memory) for processor memory and as file storage space. This gives the problem of data loss because RAM requires a constant charge to operate, and so a complete drain of the PDA's battery will restore it to factory settings. But with current revisions of Windows Mobile and Palm OS, user storage now resides on ROM. Using flash memory like the kind found on memory cards, ROM does not require a charge to hold data, which keeps information intact even with no battery power on the device.

Because RAM is used for running programs (like on a computer) and not for user storage anymore, it does not have to be very large. The flash ROM space is the thing to look out for these days, and it is a value that can vary very greatly between different devices. The Palm Z22, an entry-level PDA, has just 32MB of persistent storage, while the O2 Atom Life has up to 1GB of ROM for storage.

Expand your handheld's storage with one
of these memory cards.

Having an expansion card slot is an important feature for handhelds. This is especially significant if you want to use the PDA as a portable multimedia device for music and videos. Smaller-sized media cards are generally used on these portable devices, typically SD/MMC cards or smaller variants. SD is the most inexpensive type of memory, while formats like miniSD and microSD will cost a little bit more. Not only can you store multimedia files on the expansion cards, applications can also be installed on them.

Processors
Like desktop PCs, a handheld with a fast processor is critical for tasks such as playing games, music, and videos or for sifting through large amounts of data quickly. Palm OS devices with multimedia features or integrated wireless communications use a variety of processors from different chip makers and are available with maximum clock speeds of between 127MHz and 400MHz. The slower models will satisfy those who use their PDA for simple tasks and don't mind waiting a second after snapping a digital photo.

Windows Media for Pocket PC handhelds also use a range of processors from different manufacturers with maximum clock speeds of between 200MHz and 624MHz. For wirelessly streaming video to a Pocket PC and other processor-intensive tasks, the faster models are better choices. Take note also that a PDA-phone with a faster processor may not necessarily outperform one with a slower processor in all areas. Certain processors handle multi-tasking better than others, so a 400MHz handheld may sometimes feel snappier than one with a 520MHz chip. If possible, try navigating various devices' menus at a shop to experience their speeds -- don't just depend on the specifications.

All the latest processors regulate clock speed and power consumption based on processor load; this way, they extend battery life while improving performance. But keep in mind that faster processors tend to consume a bit more power, thus reducing battery life.

Battery
Like any mobile gadget, a PDA is only as useful as its battery life. When levels are low, the PDA is just weighing you down.

There are a few dusty old models left on store shelves that use standard alkaline batteries, but we recommend rechargeable batteries since you are able to just plug them in to recharge. Even better, look for a PDA with a cell that is rechargeable and user replaceable. You can then carry a spare or swap it out for a higher-capacity unit, which typically offers double the battery life.

In most cases, you use a handheld in minute-long spurts, so it's easy to go several days on a single charge. It's when you start listening to music, watching videos, or connecting wirelessly to the Internet that battery life is at risk. Some devices can last only a couple of hours performing those tasks.

A PDA with a user-replaceable battery allows you to
carry a spare and swap out for a fully charged cell.

One solution is to select a model with aforementioned user-replaceable batteries, though some handhelds come with internal backup memory to protect your information if the main cell dies. The trade-off is that these models tend to be more expensive and larger. Alternatively, pick a model that comes with a compact wall plug, or buy a travel charger or a third-party USB charger if you're on the road a lot.

Data input
The various handwriting recognition systems found on PDAs have their pros and cons. Graffiti 2, Block Recognizer, and Letter Recognizer all depend on how well you adapt to the software's rules. If you do that well, they are extremely accurate. Transcriber, a system found on Windows Mobile, attempts to recognise natural handwriting, but it's easily thrown off by less than perfect script. If these options frustrate you, call up the onscreen keyboard and tap out a message one letter at a time with the tip of the stylus.

A PDA with a built-in keyboard, such as the one
found on the Dopod C800, is good for cranking
out quick email messages and memos.

Handwriting recognition has its limitations, so there are a number of handhelds with built-in QWERTY keyboards. Some models with these include the Palm 680 which has the keyboard under the screen and the Dopod 838 Pro which has a hidden slide-out keyboard. Those who adjust to the small keys can bang out an email quickly. For the best of both worlds, buy an accessory keyboard.