DSL (Digital Subscriber Line) technology has been a foundational broadband solution, delivering Internet access over traditional copper telephone lines. Its widespread introduction in the early 2000s provided many users with always-on Internet without changing existing wiring.
There are several types of DSL, most notably ADSL (Asymmetric DSL) and VDSL (Very High Bitrate DSL). ADSL typically offers download speeds up to 24 Mbps and upload speeds around 1 Mbps. This asymmetry matched earlier user behavior that focused on downloading content rather than uploading.
VDSL, an advancement over ADSL, supports higher speeds: up to 100 Mbps download and 40 Mbps upload, depending heavily on the subscriber’s distance from the telephone exchange and line quality.
Latency for DSL varies between 20 and 50 milliseconds, higher than fiber or cable but adequate for general-purpose Internet use such as email, browsing, and HD video streaming. However, its performance significantly deteriorates with distance—the further from the exchange, the slower speeds and higher latency a user experiences.
DSL continues to be relevant in areas where fiber or cable rollout is limited, providing affordable Internet albeit at reduced speeds and with higher ping times.
Although emerging technologies may phase it out, DSL’s ubiquity makes it a critical bridge to digital inclusion in many rural and peripheral areas.