Get Faster Access

ADSL

By Les Freed and Frank J. Derfler, Jr
PC Magazine

April 22, 1999

Digital subscriber line uses existing telephone cable to move data from the Internet to your home or office at speeds ranging from 128 Kbps to a theoretical maximum of 8 Mbps. Unlike ISDN, which requires a dedicated pair of wires between the phone company and the user, DSL hitches a free ride over existing analog phone circuits. That signal doesn't interfere with phone service, so you can still use your phone, fax, or modem on the line as you always have.

There are many flavors of DSL, but the most common is ADSL. ADSL is asymmetric, with download speeds that are much higher than upload. Most DSL providers use tiered pricing based on different levels of download bandwidth. The speed available to you will depend on your distance from the local phone company central office.

Our throughput tests of DSL services in four locations found speeds ranging from 4 to 25 times the speed of our V.90 connection. On the average, we found cable connections to be a better deal than DSL, but DSL is a more practical solution for business users, since many businesses don't have cable television installed in their buildings.

At your end of the connection, you'll need a DSL modem, which can be an external box paired with an internal Ethernet card or simply an internal DSL modem card. Either way, the DSL service provider will typically provide the modem. Internal DSL modems install in a PCI or ISA slot in your PC, much as ordinary dial-up modems do. PC vendors Compaq and Dell now offer factory-installed DSL modems as an option on their custom-built PCs. Compaq is offering standards-based modems, which won't be useful until summer 1999, when services start adhering to these new standards. Dell offers proprietary modems for particular services in particular locations today.

Various companies called Local Exchange Carriers, or LECs in telephone parlance, are waging economic, legalistic, and bureaucratic battles over the use of last-mile telephone cables to provide DSL. The ALECs (alternative LECs) or CLECs (competitive LECs) in your area, with names such as Covad and NorthPoint, are both challenging and cooperating with the local telephone company or Incumbent LEC (ILEC), such as Bell Atlantic and U S West, in a very complex courtship. You now can get -- or shortly will be able to get -- DSL from interexchange carriers (IXCs) such as Sprint and MCI (through UUnet.) For these reasons, you might find DSL available from several carriers in your area -- or not available at all.

Many DSL providers also act as your Internet service provider. In some markets, however, you may purchase DSL service from your local phone company and Internet access from an independent ISP. And in some cases the ISP may act as your DSL provider.

The Emerging Standards

In late 1998 and early 1999, the International Telecommunication Union (ITU) approved a group of ADSL standards. Most people will eventually use ADSL service delivered in a form called G.lite. G.lite will first appear in the summer of 1999 as telephone central offices and private buildings get new DSL service. G.lite offers a maximum download rate of 1.5 Mbps and a maximum upload rate of 512 Kbps, but speeds will vary in individual installations. G.Lite will let phone companies get out of the business of selling or renting and, most important, installing DSL modems on users' premises. Instead, users will purchase modems from third parties (mail order, computer superstore, and so on) and install the modems on their own, then take the modems with them when they move to other locations.

What We Found

We signed up for ADSL services in three locations: Bell Atlantic's InfoSpeed service in northern New Jersey (near New York City), BellSouth FastAccess in downtown Atlanta, and a combination of Sirius (a local ISP) and Covad (a competitive exchange carrier) in the San Francisco Bay Area. All were ADSL. We also signed up for IDSL service, which gives you 144-Kbps uploads and downloads, in Foster City, California.

If you have ADSL service available in your area, then one or more companies has probably sent you mail or called to tell you about it. These service providers vary in how they connect their central offices to the Internet. Unfortunately, you have no way to judge these back-end connections and we can only generalize, saying that they change and evolve frequently.

Competition brings aggressive pricing. While the "standard" DSL package might call for installation and equipment fees of $200 to $600, there are many special deals. Our reviewers found $325 DSL devices promoted for $99 and other promotional offers that waived installation fees. Similarly, monthly fees for DSL vary depending on factors such as your local telephone service plan and whether the DSL service provider is also the telephone service provider. Overall services charges, including ISP service, run in the range of $49 to $150 per month for a maximum of 1.5-Mbps download speed with 384 Kbps guaranteed. Across the country, ADSL typically costs about $10 to $20 more per month than cable modems while offering slower service.

The throughput our reviewers received from DSL varied widely. One DSL installation, from BellSouth in Atlanta, provided better throughput than the average of cable modems across the country, but typical DSL throughput was much less. If you live in one of the tiny slices of the country where both services are available, then a cable modem is probably a better deal.

In some cases the installation required two visits -- one from the telephone company to check the lines for DSL and one from the DSL provider to perform the installation; but our DSL users did not have the same complaints about service that many of our cable users had.

As the sophistication of your computer system goes up, so does the potential for installation problems. We saw an installer confused by Windows NT, and we saw a nearly universal policy of disconnecting or at least disallowing responsibility for any connection to a local area network. But in our discussions with the companies, they say that they are putting agreements in place for proxy and firewall software.

While DSL is great for pulling down Web pages, it doesn't do as well at serving them up. Typically, DSL is delivered as an asymmetrical service. Our experience shows that you could put up a successful "friends and family" Web site, but that no personal DSL service will let you set up a busy Web site. A personal DSL service is not the right pipe for an e-commerce Web site, but DSL providers can offer faster and more expensive services without upload restrictions.