DSL (Digital Subscriber Line) is a technology that provides high-bandwidth (high-speed) network connections to individual homes and businesses. DSL uses the same line as your regular telephone service, but it can provide the higher data speeds because it uses digital modems.
With DSL, you can browse the Web or check e-mail without tying up your telephone line
Unlike Cable Modems, DSL service offers dedicated bandwidth, while cable modems offer shared bandwidth, which means that actual performance depends on how many other users are in the area and online at the same time.
DSL technology offers three major advantages over dial-up Internet access: much higher speeds, a constant “always-on” connection, and talk-and surf capability.
The key to Digital Subscriber Line technology is the modem; the line itself is the same telephone wire you’ve always had. In very simple terms, the DSL modem that comes as part of the service “talks” to another DSL modem located at the service provider’s location; in essence, from a user’s perspective, the modems send data back and forth, without affecting your voice calls over the same telephone line. The digital technology “converts” your line to use the additional, data capacity. As a result, DSL users can “share” the line at the same time both for digital (data) and analog (voice) calls. Thus, you can “talk” and “surf” at the same time.