By calling its Treo 600 a "smart phone," PalmOne wants to you to think that its new handheld device is primarily a telephone, secondly a computer-and perhaps forget that it is a handheld organizer running the Palm 5 operating system.

PalmOne, for those of you who need a scorecard, is the company resulting from the merger earlier this year of Palm and Handspring. The Treo 600 is the third generation of Handspring's combination of a Palm-based computer with a cell phone module, an idea that the company first explored in 2000. Unlike the previous models, the Treo 600 is shaped and sized like a phone, not like an organizer. There's a prominent stub antenna sticking out the top. There's a little VGA digital camera on the back, so you can snap pictures of the crowd when you are pretending to be dialing. And when you see photographs of the device in advertisements, the screen is shown displaying a big 12-button virtual keypad-presumably a lot less intimidating than the 35-key QWERTY keyboard that takes up the phone's bottom inch.

But make no mistake: The Treo 600 is a PDA through and through. It is, in fact, a fabulous PDA, with a brilliant anti-scratch screen that's easy-to-read, even in direct sunlight, and a nice little keyboard that makes it easy to type in names and addresses. It is equipped with a 144-megahertz processor-five times faster than the one in the Treo 300 and most other Palms.

Why, then, does PalmOne emphasize that the 600 is a phone? Because the cell phone market is roughly ten times larger than the market for PDAs. What's more, cell phone users tend to upgrade their devices every 18 months; most people seem to be far less eager to upgrade their Palm-based machines. Thus, by positioning this device as a "phone," PalmOne hopes to capture part of a larger, far more lucrative market than it has targeted in the past.

The 600 is noticeably smaller than the other Treos that Handspring has been selling for the past two years, but it's still larger than today's top-of-the-line cell phones. But more important than size is battery life: PalmOne claims that the 600 provides four hours of talk time and "up to 240 hours (10 days) standby." That's a generous estimate; in my testing, I got about two days of standby and perhaps an hour of talk time before the phone went dead. That may sound horrible, but it's actually twice as long as the Treo 300 that I used previously-a device that rarely made it through the day without needing a battery recharge. The 600 has enough battery power to get me through a full day (and sometimes even two) before I need to charge the phone again.

(I'm using the CDMA version of the Treo 600 that is compatible with the Sprint PCS network; the GSM version offers 50 percent more battery life and works with both the AT&T and Cingular networks. For people who need extra battery life, PalmOne plans to offer an external booster battery that should double the talk time-although it will also double the phone's thickness.)

In addition to the beautiful screen and the keyboard, the 600 has a five-button navigation dial in the center that makes it easy to move the cursor around the screen. There's a slot in the top of the device that holds an SD card, allowing you to expand memory to hundreds of megabytes-a handy feature,  since the 600 can double as an MP3 player. The screen is so bright that I have literally used it as a flashlight in the dark.