Sprint's original high-speed ExpressCard modem, Novatel's Merlin EX720, has been surpassed, since its launch, in performance by newer models. But if you can pick this device up for $99 with a service contract, it's still a good way to get on Sprint's nationwide, high-speed EV-DO Rev A wireless network.

Like the Apple MacBook Pro and the Dell Vostro 1310, the Merlin EX720 fits into modern laptops with an ExpressCard/34 slot Once inserted, the only visible sign that the modem is installed is a stubby little bit with the flip-up antenna. A single LED lights up green to show that the device is receiving power and a signal.

Like all current Sprint modems, the Merlin EX720 supports Sprint's nationwide EV-DO Rev A network, with maximum real-world download speeds of around 2.3 megabits per second and upload speeds of around 700 kilobits per second. EV-DO is a member of the "3G," or third-generation cellular family of technologies. So when you hear the term, this is what people are talking about. When the device is out of EV-DO range, it drops to the much slower 1x system, with speeds at around 100 Kbps. (In case you're wondering, 1x is a "2G" network.)

Sprint's high-speed data service plan is on a par with Verizon's and AT&T's. Basically, you get a 5GB bucket of data per month for $60, with fearsome but seldom-enforced overage charges. (Only Cricket, the tiny and relatively unknown cellular carrier, offers truly unlimited high-speed data.) Sprint's modems work in Canada and Mexico, but not overseas. If you're a world traveler, you'll want to go with an AT&T plan and device instead.

Though the Merlin EX720 includes connection manager software on a CD, I say skip it and download Sprint's more advanced and stable SmartView program for XP, Vista, and Macs from Sprint's Web site. SmartView is much better designed than the previous Mobile Broadband client, and it gives you a clear view of your signal strength and data transferred. It also has a VPN and a Wi-Fi connection manager built in, and quick links to Sprint support and an animated speed test screen.

Now more than a year old, the modem is showing its age in terms of speed. The Merlin EX720 fell noticeably behind the three newer cards for Sprint that junior analyst Brian K. Neal and I tested. These include the Novatel Ovation U727, the Sierra Wireless AirCard 597E ExpressCard, and the Sierra Wireless Compass 597. Its average download speed of 649 Kbps was 16 percent slower than the leading Ovation U727. The device did show an excellent peak of 2.1 Mbps down, and it had strong upload speeds that averaged 458 Kbps and peaked at 619 Kbps. In terms of signal strength, the difference between USB modems and ExpressCards in general outweighed the differences between individual models. USB modems, in our experience, got slightly stronger signals.

Choosing an EV-DO modem for Sprint isn't that difficult, because they're all pretty good, so it's hard to go wrong. But it's our job to draw the small distinctions, and the Merlin EX720's performance just doesn't quite match up to that of the newer models. I recommend dropping $30 more for the Sierra Wireless AirCard 597E if you're an ExpressCard fan, or better, the Ovation U727 USB modem if you don't have a preference.

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