What's ADSL mean?

ADSL stands for asymmetric digital subscriber line.  Let's break that down:

• Asymmetric means that the bandwidth varies.  More of the connection is devoted to downstream rather than upstream.  This means that users are able to download more files and obtain more information than they're able to send within the same timeframe.
• Digital means that the information is transmitted digitally between two devices, one onsite at the subscriber's location and the other at the DSLAM.
• Subscriber line means that this is a service delivered to a particular address over a pair of copper lines in the existing telephone infrastructure.

How does it work?

In an ADSL connection, two copper wires must be linked between the DSLAM (digital subsciber line access multiplexer) at the wiring center, and an ADSL modem at the customer premises.  These two copper wires are a part of the existing telephone infrastructure.  Since ADSL operates on a high frequency band (typically from ~26kHz to ~1100kHz), it can be used on the same copper pair as a regular, individual phone or fax line (which operate in 0-4kHz).  ADSL can't be set up through most business or corporate phone systems, as they sever the continuous copper between ADSL modem and DSLAM.  Often times, it is best if a POTS (plain-old telephone service) splitter is installed on the physical line in question.  This unit is designed to separate the dialtone from the ADSL, for two reasons.  First, so that they can be wired in different directions instead of being bound to a single line.  Second, so that there is no noise generated overtop of the dialtone that might affect voice and/or fax quality.

In the case of The Internet Centre, ADSL service is offered in many areas of both Alberta and British Colombia.  This service relies upon the existing telecommunications network, which is both owned and operated by Telus.  As a result, the service passes through some Telus equipment and wiring, and also requires some Telus involvement for adding, removing and repairing ADSL connections.  Customers of The Internet Centre do not have to deal with Telus regarding their internet connection, except on the uncommon occasion where a Telus technician must visit.  This is only the case if the problem is believed to be between the demarcation point and the DSLAM, and Telus must wire equipment to both ends in order to perform tests, inspect the pole if the line is overhead, etc.

Telus is responsible for connectivity between the provider network (in this case, The Internet Centre's main facility in Edmonton) and the customer demarcation point.  This is the point where the Telus wiring enters a facility, and often ends at the BIX block or punchdown.  In most households this is in a panel, downstairs or in a crawlspace.  In business facilities this can be in any of a number of locations.  Strip-malls and multi-business buildings can often have a single primary demarcation point where the wiring enters the premises.  It's very important to note that customers, home or business, are responsible for wiring on the inside of their demarcation point.  Internal wiring problems can slow down or completely disable a working ADSL setup.

If you'd like to know more about ADSL on a technical level, visit the Wikipedia article at http://en.wikipedia.org/wiki/ADSL