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	Issue TOC Print full article Print this page Download as PDF E-Mail this URL Flame the author     In this article Introduction IP Packet Architecture Throughput Versus Latency But Is It Secure? Executive Summary GPRS: Problem-Free Connections Verizon Wireless' 1XRTT: Safe At Almost Any Speed

We tested Verizon wireless' Express Network (CDMA 1XRTT) in and around Syracuse, N.Y. Although our tests may seem extreme--not too many people try to download e-mail while driving--we're happy to report the worst-case scenarios we encountered weren't too bad. We experienced latency everywhere, but the service's speed was adequate when we had a strong signal. When the signal is weak, though, you might as well use carrier pigeons for wireless transfers.

Verizon supplied us with a Sierra Wireless AirCard 555, a Type II PCMCIA-based cell modem, which we installed on a Dell Latitude CPx laptop running Microsoft Windows 2000. This dual-band wireless PC Card provides network, voice and two-way messaging capabilities. It has a plug for a headphone jack and can be used as a normal cell phone. An on-screen interface mimics a cell-phone screen, for making and receiving calls. The interface shows voice-mail status, signal strength and dialing buttons. Beyond providing caller-ID information, however, the computer does little more than answer, dial and deal with SMS text.

The Sierra card's antenna looked flimsy and breakable. It is not retractable nor is it permanently attached to the card. We've broken enough PCMCIA Ethernet card dongles to know this is not a good thing. You must install the Windows-only software to use the card; however, the process is straightforward. The software automatically loads a driver for the card, sets up a PPP script and loads a custom user interface for dialing and status information. We were running in about five minutes.

The card supports 1XRTT and circuit-switched CDMA connections, and is backward-compatible (albeit at 14.4 Kbps) if 1XRTT service isn't available in your area. Connecting to the 1XRTT network and obtaining an IP address took 1 to 5 seconds, depending on signal strength. You are given a three-day lease, but it's virtually useless. If you are IP idle for five minutes, you will be disconnected. And reconnecting does not guarantee the same IP address; we went through several during our tests.

For our main test, we drove about 40 miles, taking measurements in downtown Syracuse, the suburbs and on Interstate 90 going 65 mph in our Nissan Sentra. We had connectivity all the time, but in some places the throughput was so poor it was barely usable. We measured from 3 p.m. to 4 p.m., and then again from 11 p.m. to midnight. Latency was terrible all the time. Pings to www.yahoo.com usually took between 300 ms and 450 ms, and peaked at more than 800 ms. The average rate for even our best connection was 375 ms. Latency did not increase or decrease with signal strength, but throughput did. We used bandwidthplace.com/ speedtest as our speed gauge.

Verizon Wireless claims the network is capable of data speed bursts up to 144 Kbps, with average speeds of 40 Kbps to 60 Kbps. At worst we got 11 Kbps and at best almost 104.7 Kbps, the latter at night. We were surprised to see a respectable 66.4 Kbps while traveling down the highway during the day. In areas with lower signal strength, lost packets occurred frequently. In general the system was quite fast and usable. If you're in a good coverage area, the speed is better than dial-up but slower than broadband. When reception is bad, you'll likely get better results with an acoustic coupler attached to a bullhorn. --Michael J. DeMaria