Which technology delivers high-speed internet over traditional telephone lines?

• A. Fiber optic
• B. Cable
• C. Digital subscriber line (DSL)
• D. Wireless

Answer: (C)

Using existing copper telephone lines to deliver broadband carries data on higher-frequency signals alongside the voice channel, so you can talk on the phone and browse the internet at the same time. This is achieved with filters or splitters that separate voice from data, and a modem at your location connects to a DSL access point at the provider’s end (a DSLAM). The speed you get depends on how far you are from the central office—the closer you are, the faster the connection. Variants like ADSL and VDSL offer different speed profiles to suit various needs. This approach specifically uses the traditional telephone copper infrastructure, unlike fiber optic (new fiber cabling), cable (coaxial lines shared with TV), or wireless (radio waves).