(This is the second in a special three-part report on current Internet connection services. The Oct. 19 report reviewed telephone modem and ISDN services. The Oct. 21 report will review the various choices and offer a guide for moving into new services.)

Cable Modem

What it Is: A few years ago it became clear that those same cables that carry so much information to your house or place of work in the form of television signals could be used to transmit other information as well. (For more information, go to the Cable Modems.com site.)

After a few trials in test communities, cable Internet access has rolled out in areas all across the country. With the promise of 10 Mbps download speeds and aggressive pricing, cable access has taken the lead among home broadband options.

Like most options, getting broadband access over cable requires three things: geographical availability, installation and special equipment.

Geographical availability for cable is widening, thanks in part to potential competition from the phone companies and satellite dishes. Time Warner's Road Runner and TCI's Excite@Home and @Work services are the two biggest names in the cable access game, and between them they cover most of the United States' cable networks.

However, Internet access over cable does require some infrastructure improvements to the cable system. The more modern the system, the easier the modifications. Therefore, cable Internet access has spread mostly to larger metropolitan areas so far.

While it may soon be possible to buy the special equipment -- the cable modem, required to hook cable to a computer system -- in a store, the cable company generally has to come out and install a splitter on the line. Installation costs may vary.

Broadband Internet Access Options

Service Max. Downstream Speed Max. Upstream Speed Approx. Monthly Rates Phone Modem 56K 33.6K $10-$40 ISDN 64K-128K 64K-128K $30-$200 Cable Modem 10M 33.6K-10M $40-$150 DSL 384K-8M 384K-2M $40-$400 Satellite 400K 33.6K $30-$130 *Rates for single computer, non-business use. Rates for organizational use may vary and will often be higher.

Pros: Cable has the potential to be the fastest of all the options discussed here, and is only theoretically beaten out by the potential of wireless Internet systems that will be constructed over the next few years. Cable's top speed can be over what most computers can handle under perfect conditions.

Also, cable is widely-spread. While other options have had limited rollouts, many major metropolitan areas now have cable Internet access available, often at a competitive price.

Finally, the cable standards have the backing of very large companies. That means they are likely to stick around and the coverage area is likely to expand over time.

Cons: The primary problem with cable access, if it is available where an organization is located, is in the nature of the system. Unlike phone line-based solutions that travel from point-to-point (namely, from a customer to an access provider), cable forms a network between all subscribers that share parts of the cable system. This network works exactly like any other network. In other words, the more people get on the network, the more the network slows down. So, early adopters may see their speeds drop off as more and more connections are made.

Cable networks have one other thing in common with regular computer networks as well: Users can access each others' files. If you are working under Windows, turn File Sharing off when on a cable network. There are some software solutions to this problem, but it allows computer systems to be cracked more easily.

For now, at least, organizations may not be able to use their preferred ISP if they are on cable. While the debate over open access to cable systems is ongoing, in many places buyers have to use the ISP owned or partnered with the cable system.

Finally, access to the cable is not always a given for businesses. While residential neighborhoods may be wired for Internet access, and even downtown business districts (like PNN's here in Raleigh, N.C.) may have access, there is no guarantee that the building will. With cable television not being a popular item in many places of work, many buildings are wired with phone lines, but not cable.

DSL

What it is: Digital Subscriber Line technology, often known simply as DSL or xDSL, is much like ISDN in that it runs over regular phone lines. However, DSL maximizes the potential of the lines much further, possibly offering speeds up to 9 Mbps. (For more information, go to the ADSL Forum site.)

DSL comes in several different flavors, usually known by the addition of letters in front of the word. ADSL, or Asymmetric DSL is the most widely known in America, offering higher downstream (from the ISP to the client) speeds than upstream. Symmetric DSL is for organizations that need a high speed connection both ways, taking away a little of ADSL's downstream speed and adding that to the upstream speed. There are other variants, but collectively all variants are called xDSL.

Installing DSL is much like cable or ISDN. The provider has to agree to provide DSL service through the phone line, and then special equipment (a DSL router, sometimes called a modem) has to be added. Sometimes the phone line requires a splitter to attach a phone; sometimes the router performs that function. Finally, a network card is needed to communicate between the router and the computer.

Potential Download Times for a 10MB File

Type of service Transfer time 28.8K Phone Modem 47.5 min. 56K Phone Modem 24.4 min. 128K ISDN 10.7 min. 400K Satellite 3.4 min. 1.5M G.Lite DSL 52 sec. 8M DSL 10 sec. 10M Cable Modem 8 sec.

Pros: DSL is much more widely available than last year at this time, and pricing has become more consistent and consumer-oriented, eliminating an early problem that plagued ISDN. Phone companies are pushing to make DSL a good choice for business, so organizations may be able to get deals on the service.

Because it is a point-to-point connection, DSL does not have the same security considerations as cable. (All "always-on" connections can have another security problem, though, having to do with the computers having a constant address, or "location," on the Internet, making it easier for hackers to find the system. Ask your provider if they shift IP addresses to make sure this cannot happen.)

Much like with phone modems, DSL users can choose their ISP, as long as that ISP can handle high-speed connections.

Many companies are offering DSL in several speeds, using part or all of the capability of the line. Smaller organizations that do not require as much bandwidth often can choose to pay a cheaper rate for the speed they need.

Finally, a new version of DSL, called G.Lite, has been finalized, meaning that companies will begin providing it to consumers. G.Lite, while slower than top-speed DSL, is meant to be easier to set up and use, much like plugging a phone into the modem jack on a computer.

Cons: DSL has one serious flaw: availability. While many phone companies are touting their DSL service, customers are often surprised to find they cannot receive said service. Because of DSL's technical limitations, organizations wishing to use it must be within a certain distance of a central office of the phone company -- three miles, for instance. DSL speeds degrade as a function of that distance as well, so organizations on the periphery cannot always count on the best speeds.

Also, while pricing has become lower and more consistent, there are still metropolitan areas where DSL access can be almost as expensive as a high-end business solution like T1. Competition from cable access tends to lower these prices, since phone companies see DSL as their way of competing with cable in the residential market.

If you want, review information about telephone modems and/or ISDN connections.

Got any questions, comments or suggestions for Tech Notes? Contact Shane Thacker at shanethack@mindspring.com or (919)899-3746.