DSL
Digital Subscriber Line (DSL) is a broadband internet service that is delivered right through your regular phone line and is often supplied by your local telephone company. Although it uses your phone lines, it does not interfere in anyway with you telephone, caller id, answering machine, or other telephone equipment. It is typically available in speeds from 144Kb to 3Mb, but even faster speeds are available from some providers.
aDSL
A type of DSL common for residential use is Asymmetric Digital Subscriber Line (ADSL). It is asymmetrical in the sense that it can download (receive) data much faster than it can upload (send) data. Typical internet surfing mainly involves downloading data from web servers, so this asymmetry works out fine for home use. Plus this asymmetry often allows for large cost savings.
sDSL
A type of DSL that is common for business use is Symmetric Digital Subscriber Line (SDSL). With SDSL you get the same bandwidth (speed) in each direction. Although it is typically much more expensive than ADSL, it is better if you are running a web server or conducting other activities which would require a lot of data to be sent.
Cable
Cable internet access is generally offered by the same companies that provide cable TV. It works on the same coaxial cable that the TV signal comes in on, but doesn't effect your TV signal. Therefore you can use the internet and watch TV at the same time. Typically, cable internet access provide a maximum of 1.5 - 6MB of bandwidth on the system. However, everyone on your network segment is sharing that bandwidth, so performance can be much lower, especially if a lot of people in your neighborhood use the service. They may also limit your individual bandwidth, so that you will never see the peak bandwidth even when your network segment is clear. Since you are sharing the network segment with other users, there can be security risks with cable modems.
Satellite
With satellite internet access, data is sent between a small satellite dish at your home and the satellite in space. This data is then relayed to a base station that has a direct connection to the internet and acts as a hub. Especially for those in rural areas that cannot get DSL or Cable internet access, a satellite ISP can be a good way to get broadband service.
