Samsung's BlackJack, available from Cingular Wireless, is the latest of a recent glut of smart phones costing around US$200. Others include Nokia's E62, Research In Motion's BlackBerry Pearl and the LG enV. This particular device is quite attractive. In fact, one of its most attractive features leads to an unusual question: Can a mobile device be too small?

This 3.5-oz., Windows Mobile 5.0 device is light, has a great feel and is small enough for shirt pockets. The 2.2-in., 240-by-320-pixel screen is surprisingly bright and viewable given the overall tiny size of the device, and 3 Gbps download speeds made getting mail and other media a breeze.

This device has quad-band support for GPRS/GSM networks and support for the faster data speeds of HSDPA 3G service in 1900 MHz range of spectrum in the U.S. It also supports Bluetooth 2.0 and sports a QWERTY keyboard and a thumb wheel for quick access to the menus.

Business and advanced communications features include instant messaging from MSN, AOL, and Yahoo, and mail clients from Microsoft and Good Technology, as well as Cingular's Xpressmail service. And, of course, it syncs personal information and documents with your PC and Microsoft Outlook. There's also extra storage in the form of a microSD slot.

For fun, media features include a 1.3-megapixel camera, access to the optional Cingular Video and Cingular Music services, the mobile version of Windows Media Player, and support for WMV audio files and MPEG4 and H.263 video.

In other words, the BlackJack is both cute and packed with features. But has it, like some of its competitors, gotten too small to be comfortably usable?

Test drive

At 4.4 in. by 2.3 in. by 0.5 in., the BlackJack is slightly smaller, a hair thicker and half an ounce heavier than the Motorola Q. In other words, like so many other recently released smart phones, the BlackJack is small.

My first impression was that I liked the rubber coating of the unit. But when I tried to use the keyboard, I started to wonder whether it's possible for a phone to be too small -- I found data entry to be clumsy.

Thinking the problem might be me, I gave the unit to a few random people I met one day while out shopping. Most had the same response. I assume that Samsung did usability testing, so perhaps the people in my sample set had larger-than-normal hands? In fairness, however, this is certainly a problem all people face, to varying degrees, when using just about any mobile device with a thumb-typing keyboard.

Moving on, I found the Windows Mobile interface easy and mostly intuitive to navigate using the scroll wheel. Everything I needed was easy to find and self-explanatory, with the exception of the control for setting the ring volume for the phone. After searching for a while, I found that it was on the body of the device and required using the volume keys. Ring volume is not set on a per-ring basis as I expected.

Next, I tried the device's 3G capabilities. I fired up the mobile version of Internet Explorer and went to the Cingular Video site. Here I was able to view the latest CNN report as well as Comedy Central clips. The Windows Media encoded files played smoothly at what seemed to be 30 frames per second and the stream began instantaneously. The encoding was clean, though switching to full-screen mode did not make the video any bigger; it just eliminated clutter from the display.

My only complaint about the media player was that, although pressing the Back button took me to the previous screen, the video continued to play in the background. In fact, it continued until I selected a new video to play or it ended; a minor interface bug.

Surfing the public Internet with the bundled version of Internet Explorer was successful -- mostly. A few sites reported that I was not running true IE6. AJAX-driven Web sites such as Google Maps did not display properly, which is a more serious shortcoming. I attempted to install Opera for Windows Mobile 5, but that would not run properly either.

However, most of the sites I visited using the built-in IE browser displayed properly, and everything downloaded quickly. I was able to download a 2MB file in about 12 seconds, an unheard of rate for mere GPRS devices. The built-in Microsoft Office document viewer worked perfectly, and so I was able to view, edit, and share files easily and quickly.

The bottom line is that, if you are a business traveller or just want to get e-mail and video media files quickly, the BlackJack is a great unit. It's sleek, attractive and fits in your hand well. Maybe a little too well, since some usability is lost because of its size. But there always are trade-offs as devices get smaller.