Last year, T-Mobile introduced the BlackBerry Curve 8320, the first BlackBerry to support Wi-Fi with UMA technology, which lets it make calls over wireless networks. Now T-Mobile is bringing the same ability to the Curve's corporate cousin, the 8820. If you haven't heard the news, T-Mobile's HotSpot @Home service lets you make unlimited Wi-Fi calls for $10 per month. Calls you place from a Wi-Fi hot spot (including T-Mobile HotSpots) don't count against your monthly minutes total. You can also start a call in Wi-Fi mode, leave the hot spot, and then continue the free call even though the handset automatically switches back to cellular in the background. That handoff turned out to be a bit problematic in my tests, but overall, the 8820 worked exactly as advertised.

The BlackBerry 8820 follows in the footsteps of RIM's QWERTY keyboard–equipped, larger-trackball models. Its form factor is familiar by now: It measures 4.5 by 2.6 by 0.6 inches (HWD) and weighs 4.7 ounces. It's slightly bigger than the svelte Curve 8320, but that affords it a larger keyboard and screen. I had to check the documentation to confirm the 8820 was, in fact, midnight blue—the handset's plastic-and-chrome housing looks jet black under indoor lighting. Like all recent 8800-series BlackBerrys, the 8820's display has 320-by-240-pixel resolution and includes an ambient light sensor.

The phone works with T-Mobile myFaves plans, which give you one-click access to five people for calling, e-mail, instant messaging, and texting right from the home screen. You can also turn off the myFaves display to see a more traditional BlackBerry background. For Wi-Fi, the 8820 improves on the 8320 by also connecting to 802.11a networks in addition to "b" and "g" networks—including those with WPA or WPA2 security. For instance, my handset connected to a T-Mobile–supplied D-Link router as well as to an Apple AirPort Extreme Gigabit router (set to 802.11g/2.4-GHz mode) with WPA2 encryption. The 8820 lets you program multiple hot spots into memory too, so whenever you're in range of one of those routers, it will figure it out reasonably quickly (within a minute or so, on my tests) and switch over to Wi-Fi mode.

I made a variety of test calls with the 8820 over cellular and Wi-Fi networks. Calls using T-Mobile's cellular network sounded fine. There was a minor, low-level hiss in the background, but voices sounded reasonably crisp and clear in both directions. Over Wi-Fi, the hiss was fainter, and voices were equally punchy and intelligible in both directions. Reception was solid on both networks, and other parties had no trouble hearing me on a moderately busy street with cars going by, although they could hear background noise pretty clearly. The 8820 works with wired and Bluetooth headsets and also includes RIM's VoiceSignal voice-dialing technology. I also found the device's speakerphone loud enough for outdoor use.

The hand-off between the two networks (GSM cellular and Wi-Fi), however, was a bit of a problem. The T-Mobile–supplied D-Link router is optimized for Wi-Fi calling, and that one worked perfectly. It switched back and forth between Wi-Fi and GSM networks with no trouble aside from a touch of static at the hand-off point. But I had less luck with my Apple AirPort Extreme Gigabit router. In this case, the 8820 connected fine over Wi-Fi, but it dropped calls whenever I left the hot spot. I would get a three-tone error beep and a "Call Failed" dialog box before disconnection. A few test calls failed even when I stayed put, though others lasted for hours without a problem. Based on this experience, I'd steer potential customers toward T-Mobile's router, since it's easy to set up and worked fine for good old Internet access too.

Wi-Fi calling aside, the 8820 is a quad-band GSM/GPRS/EDGE handset. It doesn't support 3G, but like all 2.5G BlackBerrys, it makes the most of its EDGE connection with server-based data compression, and doesn't feel much different when surfing the Web over EDGE or over Wi-Fi. Spec-wise, it's no different from any recent model, with its 312-MHz CPU, 64MB of ROM, and 32MB of RAM (which sounds a little weak but isn't an issue in day-to-day use). Like all modern BlackBerrys, the 8820 is as stable as a cement foundation and never crashed or even froze momentarily during the entire review period.

It's also a top-notch messaging phone—but, hey, you probably knew that already. For e-mail, the 8820 supports BlackBerry Internet Service, which connects to up to ten accounts (including POP, IMAP, and most big-name webmail accounts). Corporate users can link to BlackBerry Enterprise Service, which operates with Microsoft Exchange, Novell GroupWise, and Lotus Domino for encrypted push e-mail and IT policy controls for remote management. My test unit wasn't so equipped, but retail 8820s will also come with built-in IM clients for AOL Instant Messenger, Yahoo! Messenger, Windows Live Messenger, Google Talk, and ICQ in addition to the archaic BlackBerry Messenger app.

The BlackBerry 8820 now includes a GPS radio, which is handy for getting impromptu directions via the included BlackBerry Maps application. It also works with TeleNav GPS Navigator, an optional $10 per month service that gives voice-enabled, turn-by-turn directions. (For more details on TeleNav GPS Navigator, including an extensive review of its abilities, check out our review of the BlackBerry Curve 8310, which uses the same chipset and service.)

Multimedia support is lacking, though. There's still no onboard camera, which is fine for paranoid corporate IT departments, but not so good for consumers or small business owners. Moreover, the headphone jack is the nonstandard 2.5mm variety, instead of the 3.5mm jack commonly found on BlackBerry Pearls and Curves. Still, there is Bluetooth for connecting to hands-free phone headsets. The 8820 also lacks the much-improved browser that comes with the Pearl 8130. Surfing the Web was possible using the older browser, but I found it clunky.

RIM does include its usual, competent media player app, which supports MP3, WMA, and AAC files for music, displays photos, and comes with Roxio software to transcode videos for playback on the device. Store-bought DRM-encoded media, however, is out of the question. The built-in speaker doesn't sound great but it's fine for casual listening. There's a microSDHC slot underneath the battery cover, but it accepts cards only up to 4GB. I tried a Kingston 8GB card with no luck, although a 1GB card worked just fine.

One area where the 8820 really excels is in endurance; it beats the Curve 8320, although the 8320's performance isn't shabby. On a cellular talk time rundown test, the 8820 lasted 11 hours and 29 minutes with the Wi-Fi and Bluetooth radios turned off. Over UMA and Wi-Fi, the phone ran for almost 14 hours on the same test. If you're tired of your cell phone's short battery life, this device should be on your short list.

The Curve 8320 may be a better bet for multimedia mavens because of its included camera, 3.5mm headphone jack, and smaller and lighter form factor. It's also $100 cheaper. I could argue that the 8820 is really meant for enterprise users, since many companies aren't keen on phones with built-in cameras. But with its built-in GPS and extra hours of battery life, it's also ideal for people who work outside, such as truck drivers and field operators who are away from electrical outlets all day, or for anyone who doesn't mind the missing camera. In other words, you can't go wrong with either model.

Benchmark Test Results
Continuous talk time (cellular): 11 hours 29 minutes
Continuous talk time (Wi-Fi): 13 hours 55 minutes

Compare the BlackBerry 8820 (T-Mobile) with several other mobile phones side by side.

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