By Molly Wood
(7/25/00)

So, you think you need DSL.

Perhaps you've heard about it at work or seen the commercials on television. Or maybe you desperately want higher speed Internet access, but a T1 line seems a little extreme, not to mention expensive. Whatever the reason, there are a few things you need to know about DSL before you sign up for the service: What exactly is it? How does it work? How fast is it really ? Where do you get it? And most importantly, how much does it cost?

What Is DSL?
DSL stands for digital subscriber line. The technology uses regular copper telephone lines to connect homes and small businesses to the Internet at high speeds. Those speeds typically range from 512 Kb/s to 1.544 Mb/s (nearly 30 times faster than a 56-Kb/s modem) for downstream transfers, which are downloads or file transfers to your PC. Upstream DSL speeds--file uploads and transfers from your PC to somewhere else--are usually much slower, around 128 Kb/s, depending on what type of DSL service you have.

What do these numbers mean? Simply put, you can have an Internet connection at speeds approaching those of a T1 line for a fraction of the price. Like T1, DSL is an always-on connection, which is handy if you host a small Web site, connect several branch offices, or just hate the time it takes to dial in to the Net with a traditional analog modem.

How Does It Work?
DSL uses digital technology to send oodles of compressed data over traditional telephone lines. The trick involves using special modems at both ends that encode the data and then transmit it over an unused frequency on the line. Setting up a DSL connection is a bit more complicated than setting up a standard dial-up. The line is connected to a DSL modem, which in turn, is connected to an Ethernet network card in your PC. Often, one company (such as your local phone company or a third party, such as Covad or NorthPoint) supplies the actual DSL service, while an ISP provides your Internet connection. (You typically order the whole sheh-bang from one of those companies and let them deal with the details.) One notable plus with DSL: one line can carry both voice and data, so you simply use your existing phone line to carry DSL data--convenient and practical.

What's So Great About It?
Proponents of DSL say it's both safer and faster than competing technologies such as ISDN, which tops out at about 128 Kb/s and often hovers around 64 Kb/s, and cable modems . Cable modems are DSL's closest competitors. They provide similar service and similar, if not faster, speeds, and much of the technology is the same. Both cable and DSL require special modems and Ethernet cards and provide the same always-on connection. However, cable modems are considered less secure and less reliable. Cable users share lines, much as users on a local area network (LAN) do. Therefore, the more people who are connected to a shared line, the slower your connection speed. Sharing lines also creates a security risk; hackers can easily scan the network for incoming and outgoing files and E-mail messages that could contain valuable information--much as someone might use a scanner to look for police radio frequencies or cell phone conversations.

Access Caveat
Cable modems do have one important advantage over DSL: accessibility. Because of DSL's access limitations, cable, which is often more readily available, may be a better option for those who live outside the range of a digital line. Also, in some cases, Internet traffic can drastically affect DSL rates, as can distance from a central switching station or the condition of your telephone lines. Some providers do use shared DSL circuits. They don't split the line, as cable modems do; they split the digital circuitry. Such providers often promise only "best-effort" service, meaning they do not guarantee a specific transfer rate. Other providers offer guaranteed service for a higher price. If possible, they'll dedicate a circuit to you so that your speed won't fluctuate.

Choosing the Right Service
Once you start shopping for a DSL service, the wide range of options may leave you feeling a bit overwhelmed, with good reason. DSL is confusing for most of us. But we're here to help you figure out all the numbers, names, and acronyms. Read on as we explain the intricacies of choosing the right service for your Internet needs.

What's With All the Letters?
DSL comes in several flavors that all fall under the family name xDSL. The most common are ADSL, which stands for asymmetric digital subscriber line , and SDSL, symmetric digital subscriber line.

Home users often end up with ADSL after talking to a DSL provider. That's because ADSL provides fast download rates, up to 1.544 Mb/s, and slower upload rates, from 128 Kb/s to 512 Kb/s. Home users are often more interested in downloading than in uploading or transferring files, so upload speeds aren't as crucial. SDSL, on the other hand, is a popular business option because, in most cases, it boasts the same upload and download speeds. However, quality of service and actual speeds vary, so quiz your provider before you buy.

Diet DSL
If you're getting DSL for your home, it's a good bet you'll either be getting ADSL or DSL Lite, a lower-transmission-rate version of ADSL. In fact, as more home users jack into DSL, G.lite (also known as Universal ADSL) may become the most widely installed form of DSL. One reason is that G.lite doesn't require a splitter to separate voice and data traffic, so it's easier to install. This saves you time and money. What's more, G.lite provides potential downstream data rates of up to 1.5 Mb/s. Realistically, download rates are about 384 Kb/s, with upstream rates of up to 128 Kb/s--speeds that are still loads faster than a modem or ISDN.

More DSL Options
There are other forms of DSL, too, and while you probably won't encounter them, they're worth a mention. They include IDSL (short for ISDN DSL), which is the always-on version of dial-up ISDN; HDSL (high-bit-rate digital subscriber line), which is symmetrical and fast enough to substitute for a T1 line; and RADSL, or rate adaptive digital subscriber line. RADSL is a form of ADSL... that determines your DSL connection speed by how fast data can travel on your individual phone line.

Decisions, Decisions
Confused by all the acronyms? Don't sweat it; your DSL decision isn't all that hard. What you buy will be dictated by the upstream/downstream speeds you want and which DSL providers and ISPs serve your area. Typically, you approach the ISP that offers the package that best matches your needs and select the most appropriate service the ISP offers.

Shop Smart
Before you take the plunge, find out if you're even able to get DSL at your home or business and, if so, what kind of service you can get. Here are a few factors to keep in mind as you shop for DSL.

Location, Location, Location
Unfortunately, one of DSL's drawbacks is that it's not available everywhere. You must be within two to three miles of your local telephone company's central office switching facility. To find out if you're in a DSL hot zone, call your ISP or telco or check DSL availability on the Web (or take a look at CNET Internet Services ).

Keep in mind that the top DSL speeds are optimal speeds; you can achieve them only if you're within a few miles of a switching station and you have primo network conditions. Usually, the further away you are from a central office, the slower the service.

How Much Does It Cost?
The next factor is price. Most home users can expect to pay between $40 and $50 per month for connections with approximate speeds of 384 Kb/s to 1 Mb/s downstream and 128 Kb/s upstream. Higher-end and business-class packages, which promise higher minimum speeds, start at about $90 per month and range up to more than $300 for blazing-saddle-fast service. Often, the cheapest option is to get DSL through your local telco, which sometimes offers a variety of packages or special deals. In the western United States, for example, Pacific Bell's $39-per-month package offers speeds of 384 Kb/s to 1.5 Mb/s downstream and 128 Kb/s upstream if you sign up for a year. The price includes a free dial-up account, plus a DSL modem, a network interface card (NIC), and a splitter, as well as other extras such as E-mail addresses and Web storage space.

However, Pacific Bell and most other companies charge an installation fee of up to $100 if you don't do your own wiring and NIC installation. Prices and speeds climb from there, ranging from $80 per month, with a $100 installation fee, to a whopping $328 per month, with a $200 installation fee, for download speeds of 1.5 Mb/s to 6 Mb/s and an upload speed of 384 Kb/s. You can also get your DSL from an Internet service provider such as EarthLink. EarthLink currently offers a DSL 1.5-Mb/s and 128-Kb/s package for $50 per month, including free equipment and installation and your first three months for the price of one.

What Do I Need?
One final consideration: you'll need to equip your computer to make it DSL ready. Happily, your DSL provider will give you all the necessary hardware, and most providers will even install it for you. Basically, you need your existing phone line, a DSL modem, and a PC with a NIC. Computers less than two years old should already contain a NIC. If yours doesn't have one, make sure your DSL provider includes one in your package. To avoid installation, you could install the card yourself. However, this isn't a fun process, and it's probably worth it to have your provider install the card.

Pick the Right Provider
With so many options, choosing a DSL provider may be a daunting task. Each type of service has its own benefits and pitfalls. For example, a local telco might seem less DSL savvy than an ISP but may actually provide more efficient technical support in the long run. Find out who will maintain your service, who will be responsible for fixing problems, and what you can expect if troubles do arise.

Free DSL?
As DSL becomes popular, more providers appear, which means more options for you. Among the recent developments is FreeDSL, which has begun offering free hardware, setup, and service with no monthly charge in a number of markets. The basic service includes speeds of up to 144 Kb/s, though you may have to buy your own DSL modem. One caveat: the basic connection is free as long as you agree to keep a Web advertising banner on your screen and let a targeted advertising service track you. You can pay about $10 per month to have the ads turned off or about $20 per month to upgrade to a faster connection; these charges add up to $35 per month for a 1.5-Mb/s connection.

Local Phone Companies
If you can't stomach ads but still don't want to pay a lot for DSL, your telco is, in many cases, a relatively inexpensive option. A company such as Pacific Bell, Qwest, or Bell Atlantic is already familiar with your phone service and, in many cases, is equipped to provide all the support you need, with minimal fuss and maximum accountability if something goes wrong. Simply call your phone company to find out whether you're eligible and what your options are. Local telcos have received mixed reviews, so ask around to find out the quality of service in your area.

Local ISPs
But before you sign up with your local telco, investigate your local ISP. ISPs may not be as hassle-free as your local option, but they're usually knowledgeable about the service they provide and may offer better rates. They also offer DSL from multiple carriers, which can mean more diverse--and sometimes better--service. Log on to the Web to search for Internet service providers that offer DSL in your area.

National Providers
Lastly, a few companies, FreeDSL included, offer DSL service nationwide. Among them is Flashcom, which claims to be the largest and fastest-growing provider of DSL service in the country. It now offers service in all major U.S. cities, starting at $50 per month, including Internet access. In most locations, installation and hardware is free with a two-year agreement. DSL.com is a Web-based national DSL provider, but it has a limited range. Other national DSL providers include NorthPoint Communications, Covad, and Rhythms NetConnections.

Protect Your Connection
You're almost ready to get connected, but there's one final problem. With DSL, as long as your PC is on, you're connected to the Net, which means you have a fixed IP address and host and that your electronic front door is always open. And that makes you vulnerable to hacker attacks. To compound the problem, DSL modems typically lack security features. Hackers can remotely scan your PC's ports, crash your machine, steal financial or personal information, and introduce viruses. So protect yourself. Here are a few easy ways to make your connection a little more secure.

Turn Me Off
The easiest way to make sure no one can crack your box is simply to shut it down. Reduce the number of hours you use your computer and turn it off when it's not in use. You can also physically turn off your DSL modem, but check with your provider first to make sure this won't disrupt your connection when you turn it back on. In some cases, switching off your DSL will also reset your IP address the next time you log on--a bonus.

Keep Track of Potential Holes
Your next-best hope for PC safety is to keep track of security updates and fixes for your operating system and applications. This way, you'll be the first to know if there's a potential security hole in your OS or if one of your software programs has a dangerous back door. If you run Windows, regularly check Microsoft's Windows Update page and Microsoft's general security adviser site. Mac users have a friend at MacInTouch Security Resources, and Linux folks should check the Linux Security Home-page.

Quit Your Appin'
Another potential security hazard is your software. Make sure your applications don't attract unwanted attention. Aside from your browser and E-mail client, apps such as video-streaming tools or chat programs may be running in the background, offering an appealing back door to miscreants. If you're not using them, quit applications that connect you to the Internet. It may not stop a persistent thief or ne'er-do-well, but it will deter someone less determined. Check out ZoneAlarm, handy software that flags you when one of your applications tries to make an Internet connection.

Build That Wall
Lastly, for maximum peace of mind, install a firewall, software that blocks certain data from entering or leaving your computer. We like ZoneAlarm or Norton Internet Security 2001, which is an all-in-one Internet security app that includes an excellent firewall. Surf safely!