ADSL availability gives Internet users access to more speed and flexibility than even the best dial-up (voice band) modems can provide. ADSL, which stands for Asymmetric Digital Subscriber Line, utilizes existing telephone lines to receive and send data to and from the Internet.
ADSL speed is typically between 1.5 and 8 Mbps (megabits per second), with different ADSL plans offering a choice of different speeds.
The fastest voice band modems are only capable of providing speeds of about 50 Kbps (kilobits per second). A kilobit is equal to one thousand bits, or characters. A megabit is equal to one million bits, or one thousand times as many as one kilobit. Even at its slowest speed of 1.5 Mbps, ADSL is 30 times faster than conventional dial-up.
The "A" in ADSL stands for "Asymmetric." The asymmetry refers to upload and download speeds, which are different from each other in an ADSL configuration. Speed of downloading data from the Internet is much faster than the speed at which data can be uploaded. For most in-home users this is fine, since most home computers are used for downloading information, games, streaming video or other entertainment. Rarely do home computer users have the need to upload large amounts of data to the Internet.
Businesses, on the other hand, may have servers or require the ability to upload large files. For them, SDSL is a better option. With Symmetrical DSL, uploading and downloading speeds are the same.
How ADSL Works
ADSL transmits over telephone lines on a digital frequency which is separate from the normal analog frequencies used for voice or fax transmissions. Unlike conventional dial-up, the computer and the telephone can be used at the same time, and more than one computer can also be used simultaneously. A DSL modem is required, which may be furnished by the Internet service provider or may need to be purchased separately. ADSL coverage has a limited range, typically within 2-5 miles from the telephone company exchange.
A variety of plans is available from different providers and each provider typically offers several price options depending on transmission speeds and total amount of data allowed to be transmitted. Most will also offer an unlimited ADSL option, with no limit on data transmission. The comparison chart located below offers a wide range of options from several companies, each offering different-priced plans tailored to fit individuals' needs.