What Is the Difference Between a Regular Phone Line & a DSL Line?

By Nicole Schmoll

Updated August 29, 2017

Learn about the relationship between telephone and DSL lines.
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DSL is a special type of connection used to transmit data at high speeds, for computers televisions and Wi-Fi routers. DSL uses the same wires as a phone does, but requires additional equipment from the service provider, and a subscription from the consumer, before it can function.

Regular Telephone Lines

Standard or regular telephone lines consist of a pair of copper wires installed into your home by a telephone company so that you can receive landline telephone service in your home. These copper lines have plenty of room to transmit voice calls to other phone numbers; so much room in fact that there's lots of extra, unused or leftover room if all you're doing on a phone line is conducting voice calls.


Voice calls are conducted at a frequency of 0 to 3,400 hertz, but the copper wires installed by telephone companies are capable of transmitting frequencies of up to two or three million hertz. Each type of communication operates on a different frequency. Computers, for example, communicate digitally over specified frequencies to ensure the cable is not overloaded.

DSL Lines

Digital subscriber lines transmit digital data over the unused space on normal phone lines. Because the information is digital and not voice in nature, it can be sent on the free space within the cable without disrupting the flow of voice calls conducted at a specific frequency. Because more space is used, more data is able to be sent faster across a network or from servers to individual computers. DSL lines are able to receive data faster than they're able to send it over the Internet, unlike normal phone lines, which transmit voice calls at the same speed. A DSL line service requires a DSL modem but allows you to make and receive voice calls while at the same time connecting to the Internet, much the way cable Internet doesn't interfere with telephone service.


While traditional phone lines are available virtually everywhere, DSL service isn't. A central DSL provider, such as a phone company, must offer the service to an area. If you live too far away from the provider's hub, your DSL signal will be too weak to effectively transmit data at a higher speed. If you're tired of waiting for 10 minutes to view a photo your friend sent you in an email, talk to your phone company about whether or not it offers DSL service. If it doesn't, you may be able to get cable or satellite Internet service, which provides a faster connection than dial-up service on a normal modem and traditional phone line.