ral cities Source: National Telecommunications and Information Administration (NTIA) and Economics and Statistics Administration (ESA), U.S. Department of Commerce, using U.S. Bureau of the Census Population Survey supplements. fast T-1 lines (1.544 megabits per second, or Mbs) for some time, but it was not until 1998 that higher-speed connections became available to house- holds and small businesses through digital subscriber lines (DSL) over ordi- nary copper telephone loops and through cable modems provided by cable television companies. Alternative Broadband Technologies Residences and small businesses can obtain high-speed Internet access not only through DSL and cable modems but also through wireless and satel- lite devices. 5 Digital Subscriber Line Copper wires ("loops") that extend from a telephone company's central office or a remote terminal now serve virtually every household and business The Broadband Revolution Figure 8-2. Percent of U.S. Households with Internet Access, by U.S., Rural, Urban, and Central Cities, Selected Years Percent United States Rural Urban Central cities Source: NTIA and ESA, U.S. Department of Commerce, using U.S. Bureau of the Census Popu- lation Survey supplements. in the United States. Using equipment much like an ordinary modem, tele- phone companies can transmit data at a high speed over these copper wires. DSL modems can transmit data at far higher rates than is possible over voice-grade connections because they can take advantage of capacity in the copper wire that is not used for voice communications. Asymmetric digital subscriber line (ADSL) service refers to a DSL system in which transmission capacities differ in the two directions of transit-with downloads arriving at much greater speeds than upstream communications. ADSL is particularly useful for web browsing or distributing audio or video programming, and it can operate on the same loop used for ordinary telephone calls. Thus by installing extra equipment at each end of an existing subscriber loop, or telephone l