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Cable Modems: Move Over TV, Here Comes the Internet

In many ways, cable modems offer a logical means of bringing fast access to home offices. While cable TV lines pass by more than 100 million North American homes, only 20 percent of those homes can now get cable modem service. That number will surge as cable companies roll out two-way fiber-optic networks that deliver more TV fare as well as high-speed Net connections.

But cable modem access isn't a universal solution. Questions about service, security, and scalability keep it from being the best option for everyone. Even so, the two cable services we tested delivered an almost irresistible package: connection speeds at least ten times faster than a 56-kbps modem for about $40 a month--roughly twice the price of a typical dial-up account.

Head-Swiveling Speed

Margolin's experience aside, getting set up with a cable modem is usually clear-cut. Your PC needs an ethernet card, which the cable company can supply and install, and the company will likely lease you the modem as part of your monthly fee. Total installation costs range from $50 to $150.

Compared to its high-speed rivals, cable is a bargain. Depending on where you live, you'll pay between $30 and $65 a month, with most services around $40. Most cable systems offer always-on service that doesn't tie up a phone line. About 15 percent, however, are "telco return," which require a standard dial-up line to send data from your PC to the Internet.

We sampled the two dominant cable modem services: @Home, via TCI in Antioch, California; and MediaOne Express, via MediaOne cable in Arlington, Massachusetts. At their best, these services performed superbly: One graphics-heavy Web page that took over 4 minutes to download by 56-kbps dial-up popped up through @Home in under 5 seconds. More typically (but still impressively), cable modems sped up surfing and file transfers by 250 to 1000 percent. (See "Battle of the Bandwidths" for complete results.) Users expecting more dramatic performance boosts of 50 or 100 times the dial-up speed may be disappointed; such claims refer to maximum increases and usually compare cable to a 28.8-kbps connection.

Of course, your mileage may vary. Your local cable system architecture could be faster or slower than the ones we tried. And like any fast connection, cable modem service can't relieve Net traffic that occurs outside its own network. That said, many services cache recently visited Web sites on their own servers, so popular pages and files download more quickly.

In our tests, cable performance--especially @Home's--often matched and sometimes beat that of PC World's pricey T1 line. So why don't more companies switch from expensive T1 or frame relay to a cheaper cable connection? Because these consumer-oriented packages don't provide the level of guaranteed service quality and quick repairs that corporate users expect. That could change as @Home and Road Runner ramp up their fledgling business divisions.

Sharing the Wealth

Cable modem service can deliver cheap speed in part because it doesn't give you a dedicated fast connection to the Net. Instead, it divvies up an extremely fast pipe (capable of transfer rates up to 36 mbps) between you and other people on your "node." Depending on your service provider and your location, you might share your connection with 500 or 5000 people. If you and too many of your node-mates hit the Net simultaneously, your connection could bog down. And while most cable users seem delighted with their connection rates, some denizens of the cable modem newsgroup comp.dcom.modems.cable have reported incidents of truly glacial performance--as slow as 2 or 3 kbps.

No big whoop, say most cable modem reps; they'll simply add more capacity. "Cable modems are designed to handle bandwidth on demand," says Rouzbeh Yassini, consultant to industry research group CableLabs. "We have the architecture to allow higher capacity." For its part, @Home has acknowledged occasional problems in the Fremont, California, area, and has contracted with AT&T to increase its capacity.

Anyone who encounters lackluster cable modem service might take a cue from @Home customer Tim McArthur. Dismayed by repeated service outages--one of which lasted five days--he struck a deal with TCI cable in Pleasanton, California: He would pay his monthly bill only if the service stays up the whole time. Four months later, McArthur is still getting free access. At press time, TCI was unable to say whether other users can expect the same deal. In other words, don't hold your breath.

One more issue regarding cable's design deserves your attention: Since you share a node with other users, they could gain access to your PC. Reports of rampant cable modem hacking haven't yet surfaced, but the risk is real. Security software can help, and, as "Broadband Bob" Arick, the aptly nicknamed president of cable research firm Gecko Research says, so can common sense: "You don't need a firewall, but you do need to ensure that you have print and file sharing turned off." (For instructions, see "Top Net Access Tips.")

Monopoly Money

Happy with your current ISP and e-mail address? Tough. You'll have to leave both behind if you switch to cable modem service, because all cable service is sold as part of a package that includes a high-speed communications line and Internet access. While this may simplify setup, it also limits choice. The lack of competition could also lead to price hikes; witness the tendency of cable TV bills to mysteriously rise over time.

Cable operators contend that they'd simply like to recoup the millions of dollars they've poured into upgrading their systems for Net access. But America Online, which wants to bundle its service with cable modem service, is lobbying the federal government to give all ISPs access to cable companies' pipelines. Other ISPs want the same thing, as does the nonprofit Media Access Project, which would like to open the pipelines for reasons of freedom-of-choice rather than for profit. For now, anyone who wants to choose a broadband ISP should check out DSL.