Digital Subscriber Line (DSL) is a "last mile" service that allows consumers to access the internet by using their existing telephone lines.
While both DSL and Dial-up internet leverage existing telephone lines, DSL uses a frequency that allows calls and data to be transfered at the same time without interference allowing for users to both talk on their phone and use the internet.
Most commonly "DSL" refers a Asymmetric Digital Subscriber Line, where the download and upload speeds are different though there are 14 different types of DSL service.
However the term DSL may also refer to VDSL2 (Very-high-bit-rate digital subscriber line 2) which is the latest and fastest version of DSL that allows providers to offer integrated, HDTV, home phone and home broadband service all through one line.
To help you find the best provider, we've compiled a full list of all the DSL providers in the United States.
Should You Get DSL Internet?
While there are faster technologies available such as cable and fiber, DSL coverage is virtually everywhere. With that in mind, it can be a great solution to getting wired internet access, just make sure that the plan you sign up for supports you internet usage habits.
Large Coverage Area
Because the existing telephone infrastructure is available virtually everywhere in the continental United States, DSL it is one of the most widely available internet services in the United States.
Use Your Phone While on the Internet
While DSL isn't the fastest internet service available, it is a huge upgrade over dial-up, with the added benefit of being able to use your phone and your broadband connection at the same time.
One of the biggest drawbacks to DSL is that it even though it uses existing infrastructure, reliable service requires central offices to be placed relatively close (just over a mile) to where customers reside to receive optimum service.
Chances are if you don't have DSL service available in your area, it's because DSL providers haven't established a central office close enough to where you are.
Most DSL technologies use asymmetrical data transfer which means that consumers download speeds will be much faster than their upload speeds. While this isn't an issue for typical web browsing, doing any sort of transfer that requires substantial upload bandwidth (such as Skype, video gaming, and uploading Youtube videos) will be much slower than other technologies such as fiber or cable.
If in doubt whether a DSL plan you are considering is enough for Skype or other upload intensive programs, we recommend looking for upload speeds of at least 1mbps.
How it Works
DSL service uses the existing phone lines that were originally designed to transmit phone calls to provide broadband access.
Since these original phone lines are based on a pair of copper wires, advancements in technologies have allowed engineers to squeeze much more than data than is required to transmit traditional phone conversations.
For a detailed overview of how the technical aspects of DSL broadband works, here is a good overview.
In 2013, the FCC conducted a study showing DSL customers only received 85% of the bandwidth they were paying for during peak usage times. This is up 1% from the 2012 study.
Furthermore, the 2013 study also found that the average latency (a key metric for how fast your internet connection "feels") for DSL providers was 44ms which is substantially higher than both cable and fiber.