What is DSL internet?
DSL is broadband delivered over the copper telephone wiring that was already in the ground. It is the oldest thing still sold as broadband, and for millions of homes it is still the only wired option.
The short answer
DSL stands for Digital Subscriber Line. It sends data over the same copper pair that used to carry a landline telephone call, using frequencies the voice call did not use. That is its whole trick, and it is why it was able to reach almost everyone almost immediately: the wire was already there.
It is also why it is slow. Copper was never designed for this, and performance falls off with distance from the telephone exchange. Two houses on the same DSL service can get very different speeds purely because one is farther down the line.
How it compares
| Measure | DSL | Cable | Fiber |
|---|---|---|---|
| Medium | Copper phone line | Coaxial | Glass |
| Typical download | Tens of Mbps | Hundreds | Hundreds to 1 Gbps+ |
| Upload | Very limited | Small fraction of download | Often equal to download |
| Affected by distance | Yes, heavily | No | No |
| Affected by neighbors | No | Yes, shared node | Largely no |
| Direction of travel | Being retired | Being upgraded | Being built |
Why it is disappearing
The companies that own the copper are not investing in it. Where they are spending, they are spending on fiber, and in many markets they are actively retiring copper rather than maintaining it. If you are on DSL today, the realistic question is not whether it will improve. It is whether anything else has reached your street yet.
That question has a real answer, and it is address-specific. Providers report to the FCC which locations they can serve, on which technology.
If DSL is genuinely your only wired option
It is for a meaningful number of US homes, and the honest advice is not to pretend otherwise. Two things worth knowing:
- Fixed wireless has become a real alternative. A cellular signal to a receiver at the property now beats DSL in a lot of places, installs in a day, and does not care how far you are from the exchange. See fixed wireless providers.
- Satellite reaches where nothing else does. Latency is higher for reasons of physics, but it is a genuine option of last resort. See satellite providers.
More on what separates the wired technologies: fiber vs cable.