What is DSL, and what benefits and advantages does it offer?

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. Over the last few years, DSL has become widely available, even in rural areas. While early DSL applications were plagued by installation and/or service problems, advances in technology, increased deployment, and higher demand have eliminated most of the “growing pains” and led to improved service quality. As a consequence, DSL has become a reliable service to meet the needs of customers who demand high-speed Internet access.
DSL technology offers three major advantages over dial-up Internet access: much higher speeds, a constant “always-on” connection, and talk-and-surf capability.

1. Speed – DSL can deliver more than 100 times the network performance of a dial-up modem. While exact speeds vary, depending on the service plan or network capability, most DSL connections easily outperform standard modems by a factor of 20 or more. In essence, DSL works on the unused (high) frequencies of your phone line. DSL modems contain an internal signal splitter that directs voice signals to the voice (low) frequencies and data signals to the higher frequencies.
2. Access – a DSL connection is "on" all the time. DSL users do not have to dial their Internet service provider each time they want to "access” the Internet. You should be aware, however, that an always-on connection, such as DSL, does have security issues. It’s a good idea for DSL users to install personal firewall products on their home networks to guard against external attacks.
3. Talk and surf – with DSL, you don’t need a second line to keep your telephone line “open.” With the splitter sending the voice and data signals to “different parts” of the line, DSL users enjoy simultaneous access to both the telephone (voice) and the computer (data). Thus, DSL customers do not need a second line for their Internet access.