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Introducing DSL and Cable Connections:The Proof Is in the Wiring

Although the telephone network system is now modern in many ways, its underpinnings haven’t fundamentally changed since the early 20th century. The telephone network consists of pairs of copper wire that connect homes and businesses with a telephone company’s central offices (CO). The phone company use switches in its COs to connect you to your destination when you make a call. The switches are designed to limit the range of frequencies — called bandwidth — that a phone call can use. The bandwidth is roughly 3,000 cycles per second (Hz), enough to recognize a voice but not much more. Those limits prevent today’s analog modems from pushing more than approximately 56,000 bits per second, or 56 Kbps, through the telephone network. (That 56 Kbps speed varies, mostly downward, depending on the condition of the copper wires you’re connected to.)

TipWhat does all this mean to you? Improve your modem and the wiring, and you get faster Internet access. Two of the most commonly used broadband alternatives are

Cable television (CATV): Although CATV companies don’t provide service to as many residences and businesses as the telephone companies do, their fiber and coaxial cable networks can carry much more bandwidth than telephone wires can. CATV networks don’t have the 3- to 4-mile limits that DSL has. Typically, you can get Internet cable through your CATV company if the company offers it and if the company serves your neighborhood.

Digital subscriber lines (DSL): Designed to skip the restrictions of the traditional telephone system by making an end run around the voice switches, DSL rewires your existing telephone setup. Your local telephone company can connect your computer to new equipment that provides more than ten times the speed a dial-up modem can.

The main limitation of DSL is that traditional copper wire can carry a high-speed connection for only a few miles. Your telephone company can tell you whether it can provide you with service.