I have had DSL for some time now, and have enough experience with it to give you some information from the consumer’s point of view. My DSL provider, as well as my ISP, is SBC. Southwestern Bell uses it’s affiliate, PacBell, to actually provide the Internet connection, while using it’s own system for the DSL. 

Cable modem uses your cable television line for net access, while DSL uses your existing telephone line. It is called asymmetric because the downstream, or download rate to your computer, is different than the speed of upload, or transmission to the Internet. Just like your existing analog modem, it plugs into your phone jack, but there the similarities end. It operates on a different frequency, and can be used at the same time you use the phone. With a dial up modem, you use one at a time, the phone, or the modem. DSL is instant on (if you leave the modem on, otherwise it only takes a moment to sync up after turning it on) and provides net access at speeds up to 50 times faster than a 28.8 Kbps dial up modem.

To illustrate the speed in actual consumer, non-advertising promotion, I’ll use my system as an example. Prior to the DSL, I used a 56K, v90 dial up. SBC was also my provider, which makes the example more valid. My 56K was actually a pretty good one, with consistent connect speeds of 42-44K, which is slightly higher than the average 56K dial up. I was able to download about 16MB of data in around one hour. Remember, this is an average, taken at different times, on different connections, with different data, etc.. Sometimes it was higher, sometimes lower, but this is a pretty accurate average. My DSL will download that same 16MB in an average of around two and a half minutes. The speed difference is so great, that I no longer use a download assist program, that resumes after a disconnect in order to prevent starting over. I simply download again, if necessary. I don’t know if it is because of the DSL, but I have far fewer disconnects with it, as opposed to the dial up. The DSL account also includes a dial up access in case the DSL goes down, or you need access while away from home. Unlike the cable modem, DSL lines are private, just like your phone line, because they use your phone line. This makes them more secure, and can mean faster access speeds. Since cable modems are shared lines, there are security concerns, and as more people come online, the access speed decreases.

My nephew had a DSL line until he moved, and then had to switch, since DSL was not yet available in his new location. He had Roadrunner put in, and was told that he was the first and only subscriber in that area. Since Roadrunner advertises speeds of up to 2Mbps, he hoped to achieve near that speed, since he was the only one in that area. Nope. While he occasionally hits a maximum speed slightly higher than the maximum speed of his previous DSL account, the average speed is less. Remember, this is with his access being the only one in his area. When other subscribers come online, he can expect the speed to decrease. He says he will switch back to DSL when it becomes available in his area. Security is less a concern for him, as he has managed to set up Linux for his system, and that is a more secure setup than Windows. Since DSL uses the phone line, it is not affected by the number of users for his ISP.

I prefer DSL to cable modem, as I followed cable modems for almost two years before I chose DSL. They have two deficiencies compared to DSL; consistency, and security. If you take precautions, the security issue can be fairly easily resolved. The same is not true for the consistency. DSL appears to give more consistent speed than cable. However, if your choice is a dial up, or cable modem, get the cable modem! It is so much better than a dial up, this is a no brainer. I simply prefer the DSL.

Perhaps a word is in order here about advertised speeds, for both cable, and DSL. Cable modem advertises speeds “up to 2Mbps”, while DSL is “up to 1.5Mbps”. I overlooked that when I started, and was disappointed in my DSL. When I looked into the claim, I realized I was thinking in terms of megabytes, while the speeds are in megabits. To convert, you need to do a little simple math. You take the size of a file, measured in bytes, divide by eight, and take seventy percent of that figure. That is now in a download bit size. Example; take an 800k file; divide by 8, giving 100k; take 70%, giving 70k. This 70k is now in the size comparable to the advertised speed. For a 2Mbps cable, converted to match a computer file, would be 2,000,000/8 = 250,000 x 70% = 175,000, or a 175k size file. Not even close to two megabytes, but keep this in perspective. Compared to a dial up modem, it is much faster. Same for the DSL. The reason for dividing by eight, is there are eight bits in a byte. The seventy percent is due to “packet loss”. When you receive data, it is sent in packets. A packet is a self contained data package, 12k in size, and contains your data, where it came from, where it is going, what data it contains, and what part of the total package it is. When all the packets arrive, they are assembled into the total data requested. Part of this process is a loss of some of these packets, called packet loss. This figure is, according to the above is around thirty percent, hence the reduction to seventy percent in the above example. Since the packets are designed to accommodate this, the sending server retransmits the lost packets. 

The only fly in the ointment is the requirements for DSL. Computer requirements are the same for either cable or DSL, and both need clean lines. If your phone line is old, or in otherwise bad shape, it probably will not meet the requirements for DSL. The biggest potential problem is distance from a switching office. Your plug must be within 17,500 feet of your switching office, as that is the current limit for DSL (that will change in the near future). This figure is for the LINE, not as the crow flies. To do a preliminary test to see if DSL is available in your area, go to [www.swbell.com/DSL] and click on Availability. This will take you to a page where you enter your area code and phone prefix. This will indicate if it is available for you. If you want it, call in and the phone company will take one to several weeks to actually test the quality of your line. If it passes, they will set you up for installation. The best way, and the one being promoted, is the do it yourself. You will save a lot by doing it yourself, and it is easy.

If you decide the DIY is the way to go, you will be shipped the needed items. Included will be a DSL modem, a fastEthernet card, OR a USB setup, cables, and filters. The NIC, or USB goes in your machine. Since you connect through your phone line, you unplug the phone, and plug in the filter. Your phone plugs into the front socket, the DSL into the left socket, and your answering, or fax machine into the right plug. This filter is the main one, and goes where your Internet machine is. The DSL side socket is connected to the DSL modem, which connects to the NIC, or USB. Included in the kit are several individual filters. These are used to connect your other phones in order to filter the DSL signal. Simply plug this filter into the wall socket, then plug your phone into the filter. This DIY installation saves $198.00 ( I hear this drops to $150 soon). Install the included software, turn on the modem, and enjoy. 

While I only have one machine hooked up to the net, it is becoming popular to share a high speed connection among several machines. The ISPs don’t like it, but as long as you use a single IP, there is not much they can do about it. They are trying with a protocol called PPPoE (Point to Point Protocol over ETHERNET) to prevent you using more than one machine on a single connection, but people are finding ways around it. I helped a friend set up three machines at his house. He wanted to connect his and his wife’s computers to a single DSL. His provider set him up with a PPPoE. We networked his and his wife’s computers with 10/100t, and set up a proxy server. This allows a single IP, the main concern of the ISP, to be used by multiple machines. He uses his machine at the same time his wife is online, both on different sites, downloading, browsing, and both at DSL speeds, with no interference from his ISP. Cool!

While I think DSL is better than cable modem, you can’t go wrong with either. This is a 24/7 connection, permits fast downloads, fast browsing, and voice. Video on demand is still a ways off however. While you can watch some video clips at a normal speed, movies are still too much for this speed. VoDSL is supposed to take care of this. If you want more info on DSL, go to [www.dslprime.com] and subscribe to their newsletter.  The real world comparison shows them to be a virtual wash. You need it, you want it, get it!