What is DSL? It is short for Digital Subscriber Line ( or loop). You will see variation (x)dsl, with one of the most common being ADSL. In a nutshell, it is a technology that allows the telephone company to push faster speeds across twisted pair (your telephone line is a twisted pair). ADSL refers to Asymmetric DSL which means that the speed is primarily on the download side. You may hear things like 2mbps down and 500k up. This means you will receive web content at the rate of 2 megabits per second and content you send up is going at roughly one quarter the rate (500k). For consumers this is ok, since most of your "up" content is simply requesting a web page. Your down content (the web page) is typically much larger and so the need for greater speed.
In Calgary Telus has the distinct advantage over other DSL suppliers, that being they are the last mile supplier. What that means is that since they own the copper that goes into your house or business, they own the rights to the "last mile" and so anyone providing DSL has to run across their last mile. Due to CRTC regulations, telcos (telephone companies) are obligated to provide access to the last mile to other third parties, but of course they don't do this for free. The net of it is no matter who you contract DSL from in Calgary, at some point it will run across the Telus system. There may be small pockets of exception to this but for at least 99% of Calgary, this is the case.
DSL Suppliers to the Calgary Market:
Telus - the biggest supplier in Calgary- they service both consumer and business.
Nucleus - services both consumer and business
Radiant - services both consumer and business
Bell - in Calgary I believe it to be only business (in Ontario & Quebec they serve consumers also)
Allstream -in Calgary I believe it to be only business (in Manitoba it includes consumers)
Equipment required to get DSL:
The primary thing you will need is a DSL modem. One of the more common brands is DLink. Although the DSL suppliers would prefer you purchase the modem, you can also for an extra monthly charge rent it as part of the service. They are not all that expensive so if you have the opportunity to buy it, it works out better over the long term. The other thing you run into are little phone filters that get attached to each phone in order to block or filter the dsl portion of the signal from the voice portion. These things are in my mind pretty much a nuisance.
There is an alternative! You can install a pot splitter at the main entrance of the phone line. By the way pot in this context means "plain old telephone".
Don't forget to add either a DSL router to act as a firewall or if you are using Windows XP make sure you activate the firewall service. DSL connections are designed to be "always on" and so if you don't take precautions it will be when you are hit not if.