World Wide Web versus World Wide Wait


What is DSL?

Invested a decade ago by Bellcore, digital subscriber line service uses advanced electronics to send data over conventional copper telephone wires. While today’s analog modems top out at 56,000 bits per second, DSL devices will be able to send data at up to 7 million bits per second.

How does it work?

Traditional analog modems translate the digital language of computers into a narrow band of sound waves that are sent over phone wires and converted back at the other end into digital bits. DSL modems also use analog signals, but they’re spread over a range of frequencies 100 or more times greater. That spectrum is sliced into dozens of narrow bands, as if 100 modems were sending signals over one wire at the same time.

Why isn’t DSL widely available?

Adoption has been hampered by high prices and a lack of standards. Phone companies were reluctant to push DSL because it could cannibalize older, higher-priced services such as T-1 data lines, which move 1.54 million bits per second. DSL also required phone companies to install a special "splitter" at each home or business to separate data and voice signals on the wire. Now, Microsoft, Intel, Compaq, and the regional phone companies are backing a new "DSL lite" that doesn’t require a splitter. That saves a bundle in installation, but it limits data speed. With DSL lite, bits can flow into the PC at roughly 1 megabit per second and back out at a relatively fast 384 kilobits per second (KBPS).

How do cable modems work?

Data from the Net flow into the home over the same coaxial cable that carries TV signals into 60 million U.S. households. The data are carried in a "channel" just like NBC, but a cable modem splits them off and directs them to the PC. Cable operators have one nagging problem: Some 80% of their systems aren’t designed for two-way traffic. That means that while you get data at speeds up to 10 megabits per second, you send data over the phone line at 33.6 KBPS.

What about satellites?

The satellites that deliver television from the heavens can also transmit data. Hughes Electronics Corp., whose DirecTV dominates the direct-broadcast business, offers DirecPC, with data rates of up to 400 KBPS. Signals collected on pizza-size satellite dishes are split and routed to the TV and the PC. Satellite systems are only one-way now, but by next summer two-way dishes will be available.

Who Should use which ones?

Few businesses are served by cable, so corporate customers are far more likely to use high-speed data services from phone or satellite companies. In the home, it’s a different story: Cable services offer by far the fastest download speeds at the lowest rates. Their pokey upload speeds will become less of a drawback as more cable systems upgrade for two-way traffic. Still, don’t rule out DSL, where prices are expected to fall to nearly the same level as cable by next year. DSL does have other drawbacks: Customers need to be within three miles of a phone-company central office to get optimum DSL performance, and it’s not well-suited for carrying video signals.

Aren’t Microsoft and Intel playing both sides of the fence?

They are. Both want to promote wider use of PCs, and both worry that slow Net access could hurt PC sales. Microsoft has invested more than $1 billion in cable companies such as Comcast and @home. Likewise, Intel is spending millions on internal research into DSL, cable modems, and satellite data systems.

How the Systems Stack Up Today





DSL LITE $40 to $100 384 to 1,500 384 to 512
DSL $40 to $200 144 to 1,500 128 to 1,100
CABLE MODEM $30 to $60 800 to 3,000 33.6
SATELLITE DISHES $20 to $130 200 to 400 33.6
T-1 $1,200 1,544 1,544

Article written by Andy Reinhardt, Business Week, Feb. 16, 1998, page 83.