In the old days, life was simple. Your only real choice for accessing the Internet was whether your dial-up connection used the U.S. Robotics V.90. modem or the Rockwell K56Flex. Some ISPs supported both, some didn't. Oh sure, if you were independently wealthy you might consider ISDN or a satellite hookup where you could pay for every minute or kilobyte of high-speed hookup, but those weren't serious options for most of us.

Now you can get a broadband Internet connection for less than you spend each month on your weekday morning latte, and that's not counting the lemon Danish. But first there's a BIG DECISION to be made. DSL or Cable? To help with that choice, here's a quick review of the two technologies.

     DSL (Digital Subscriber Line) is actually a group of technologies, any of which can provide high-speed Internet access over a standard telephone line, as long as you are close enough to a Central Office where the phone company locates their switching equipment. DSL provides a direct dedicated (not shared) connection between your DSL modem and a DSLAM (Digital Subscriber Line Access Multiplexer) at that central office. The most common form of DSL is ADSL, or Asymmetric Digital Subscriber Line. It's called asymmetric because it delivers a higher downstream transmission (from the Internet to your computer) than it does upstream (from your computer to the Internet).

     Cable Internet access uses the very same cable that brings cable TV into your home, by reserving some of cable bandwidth for Internet traffic. The cable company has their own equivalent of a central office, but the cable between it and your house is shared not only between TV and Internet, but also between you and all of your neighbors that subscribe to the same service. Incidentally, cable Internet is also usually asymmetric, with more channels given to downstream traffic than upstream. Most of the time that's the best solution, because normally you will be downloading entire web pages and all their graphics while uploading an occasional keystroke.

     With cable, distance is not the issue so much as whether the cable has been routed to your street yet. Sharing though can be a big issue, because the transmission can get slower and slower as more people in your neighborhood try to download those web pages and all their graphics.

     Now, to decide which of these options is the best for you, here are some things to consider:

1. Availability. You may live too far from the central office to use DSL, or cable may not have come to your neighborhood yet. If you only have one or the other, the choice is made for you. Many areas have both, but generally DSL is more widely available in business areas while cable is pretty much restricted to residential.
2. Cost. DSL packages vary widely. Find out not only the rate but whether they charge for the modem and installation. Often these are free but require a minimum contract period. Because cable companies include basic TV service (whether you want it or not), they often feel justified to charge a few dollars more per month than comparable DSL service. Of course if you want crystal-clear reception to 50+ channels anyway, that fact might sway your decision. With both cable and DSL there may be options on cost, with more expensive packages offering greater bandwidth. Which brings us to the next consideration.
3. Speed. Your DSL and cable providers can both give you numbers for upstream and downstream transmission rates, but take them with a grain of salt. Those are maximum rates at best, and no matter which connection option you choose, it is subject to the conditions prevailing at any moment on the Internet on the other side of the central office. Both DSL and cable use the same shared links to the Internet, so no favoritism there. Cable though can be further affected by the amount of local traffic. Ask around your neighborhood to see what kind of experience to expect. Often it's no problem at all, but here and there things can get pretty grim, and that's something you want to know before you lay down your money.

     One last thing to consider is the reputation of the companies. In practice DSL and cable have more similarities than differences, and the quality of your service could very well depend more on the service provider than on the technology you choose.

1. Because it is shared, cable is not secure.
   A common misconception is that because all of the cable subscribers in a neighborhood are on the same cable and do form a network of sorts, it is possible for your neighbors to browse your computer just as if you were all on the same LAN. The truth is, not only do many cable companies encrypt your traffic with unique subscriber keys, but upstream and downstream traffic is carried on different channels, and cable modems cannot monitor the upstream channels. Your neighbors have no more access to your computer that any hacker on the Internet would (and that's the subject of another tech tip or two).
2. Running a server on your cable connection won't affect the other subscribers.
   This is technically true, but what matters is that servers typically create much more upstream traffic than normal web browsing. There is a limitation in the TCP/IP protocol itself that causes downstream traffic to slow down as much as 80% when the upstream channel gets saturated. This Internet phenomenon is called 'upstream saturation'. A few servers in your neighborhood may not matter but too many will create a crunch for everybody, and for this reason some cable companies prohibit servers on their connections.
3. You can only get cable Internet if you subscribe to cable TV.
   It's actually up to the cable provider. Since the TV signal is already on the cable, it takes an extra step to block it out and there might be an extra charge for this 'service'.
4. DSL is easy to get and easy to install.
   These are both 'iffy'. IF you live within 17,000 feet (about 3 miles) of a central office (by the length of the wire, not 'as the crow flies'), and IF your phone company offers DSL, and IF they aren't backlogged on installation, and IF there is a clean, quiet phone line with no crosstalk already coming into your home, then getting DSL is easy. That means at least 25% of us are just flat out of luck. As for installation, self-installation is cheaper and therefore more popular, but potential problems abound. For example, noise on the electrical line can get transferred to the phone line through the DSL modem, so if you have poor house wiring, dimmer switches on your lights etc., be prepared for some headaches getting your DSL to run without errors.
5. DSL can share your home phone line and won't interfere.
   Yes, you can usually run DSL on the same line you use for regular telephone service, and even do voice and data at the same time, but you must put a special filter on each extension where you have a phone plugged in. These filters come with your DSL service.
6. The DSL upload capacity has no affect on the download.
   Most residential DSL service has a maximum upstream capacity of 128Kbps. DSL is affected by upstream saturation just like cable, because this is a limitation of the TCP/IP protocol and not of the type of Internet access. This means that if your upload traffic approaches the limit, for instance because you are sending a very large file somewhere, your downstream speed will drop noticeably. Unlike cable, at least you only have to worry about your own traffic and are not affected by what other subscribers are doing. If you mostly just browse the web and send text e-mail, you won't need to concern yourself about it at all. However, if you frequently have large uploads for any reason, you might find out if your DSL provider has any upgrades with higher upstream capacity. And yes, it will cost you more per month.