DSL is the original high-speed broadband solution. As a technology, it piggybacks on existing twisted copper phone lines and uses them to transmit digital data alongside traditional voice transmissions.
DSL stands for “Digital Subscriber Line,” which describes how it works as a business — customers subscribe to a digital line alongside of or instead of a landline phone subscription.
DSL has gone through several major changes in recent years, constantly updating in order to compete with technologies like cable and fiber that offer overall faster download and upload speeds. This has led to the popularity of VDSL2, ADSL, and other DSL “varieties” you’ve probably seen while shopping for home or business Internet connections.
Most common types of DSL
|Acronym||Description||Type||Download speed||Upload speed|
|ADSL||Asymmetrical Digital Subscriber Line||Asymmetrical||8 Mbps||384 Kbps|
|ADSL 2+||Asymmetrical Digital Subscriber Line 2+||Asymmetrical||20 Mbps||850 Kbps|
|VDSL||Very High Bit-Rate Digital Subscriber Line||Asymmetrical||52 Mbps||2.3 Mbps|
|VDSL2||Very High Bit-Rate Digital Subscriber Line 2||Symmetrical||100 Mbps||100 Mbps|
|SDSL||Symmetric Digital Subscriber Line||Symmetrical||1.54 Mbps||1.54 Mbps|
Is DSL the only option in my area?
Most customers have access to at least two broadband technology options. DSL is one of the most common, with coverage over a full 90% or more of the US. 
Cable and fiber are common alternatives to DSL. You can check the specific options in your neighborhood using this zip code coverage tool:
Compare DSL to other options in your area
Factors that determine DSL speed
DSL is different from cable in that the distance between the provider and the subscriber has a huge effect on the speed you’ll get when you hook up your laptop and run a speed test.
As with most budget Internet options, you may also find that speeds slow down when broadcast over Wi-Fi in your house, and that it may be preferable to hardwire PCs, gaming consoles, and other bandwidth-intensive devices that could benefit from a direct ethernet connection to the router rather than the convenience of Wi-Fi.
1. Distance from DSLAM or “local office”
If you’re within 1 mile, the speed should be around the download rate advertised in the DSL provider’s marketing materials.
Around 2–3 miles, the speed can be expected to slow down considerably and you may encounter issues with packet loss.
Beyond 3 miles, customers would start to have problems. Unfortunately, determining your distance from the local DSLAM isn’t a simple matter. Generally, DSL providers will simply promise that they can deliver speeds in the neighborhood of those advertised, and that customers who live too far away from them to get reliable speeds will simply not be serviced.
2. Modem and router type
In some cases, upgrading your modem and router can improve your connection speed since older devices are not able to support the most recent speed upgrades from your provider. This hold true for “gateways,” the term used for the combination modem/router boxes commonly provided for customers who lease their equipment directly from the provider rather than purchase their own outright.
Wiring some of your devices such as PCs or gaming consoles directly to the router using ethernet is another common and helpful solution. Wi-Fi is convenient, but it generally doesn’t perform as well as a real wired connection when it comes to speed and latency. Particularly if you have a large residence with multiple devices crowded onto a single Internet connection, using the LAN ports on the back of your router to connect ethernet to some devices will likely save you a few Mbps and shave some milliseconds off your ping.
DSL vs cable: is DSL always slower?
DSL gets a bad rap in the broadband world since the top speeds offered are twice as slow as cable, and several times slower than fiber. That said, there are some benefits to DSL service, and even suburban and urban customers can find it to be preferable in some areas.
The main culprit here is peak-time slowdown. This is a common problem in neighborhoods serviced by coaxial cable Internet connections, as the network gets “congested” when everyone gets home from work and switches on Netflix. While DSL is a direct line to the Internet provider, cable connections are “shared” across dozens or even hundreds of houses. Cable providers assume that everyone won’t use their maximum bandwidth at the same time, and as a result many neighborhoods wind up oversubscribed.
DSL can be an attractive alternative in these neighborhoods since the speed, even if it’s a modest 35 Mbps or so, will always be 35 Mbps, regardless of what the neighbors are up to.
Conclusion: DSL speeds vary widely based on local network setup
Ultimately, DSL will always be perceived as the “budget” option since the raw speeds offered tend to be so much lower than cable and fiber. For rural customers, it may be the only option, but thankfully advances in the technology have improved DSL to the point where it can more than handle modern uses like streaming Netflix, chatting on Skype, and gaming.
References and Footnotes
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James Webb is a tech and gadgets expert with a focus on educational content development. He draws on his background in the startup world to make complicated technologies and topics easy to understand for normal folks.
Questions & Answers
3 ANSWERED QUESTIONS
Can I use my own modem with DSL service?
Yes, but make sure it is compatible with DSL and your internet tier. Also consider that some providers don’t allow you to use your own modem with their service regardless of connection type. The easiest way to check is to call your internet service provider directly.
How can how far can my house be from the DSLAM or local office/exchange before I have problems?
The maximum distance a residence can be from the DSLAM is up to 20,000 feet (around 4 miles). Keep in mind, the longer the wire has to run, the slower the data rate will be due to the lower frequencies.
That said, issues with service quality are often due to other factors beyond just distance, such as network degradation in old copper cables.