rants. 6 Cable Modems Cable television systems use coaxial cable to distribute television signals from their central facilities, or "headends," to subscriber premises. Histor- ically, these were one-way distribution systems built with coaxial cable and microwave radio systems, but in the 1980s they evolved into hybrid fiber- coaxial cable or "HFC" systems, using fiber optics to the subscriber's neigh- borhood and coaxial cable the rest of the way. The HFC cable system design improved the quality and reliability of cable systems and allowed the systems to increase their total bandwidth, some of which is now used for broadband Internet services. These HFC designs reduce the amount of coaxial cable in the upstream path that signals follow from the home to the network. Because the coaxial part of the network limits the capacity of the return channel, shortening the coaxial cable in the return path increases the capacity and reliability of the upstream path. The Broadband Revolution The cable industry and its suppliers initially experimented with many forms of two-way data communications over cable systems. In the 1990s a cable industry research consortium developed a standard for data commu- nication over cable that has been embraced by most of the cable industry. This standardization permits many manufacturers to compete in the sup- ply of compatible equipment and allows retailers to limit their inventories of cable modem equipment. It reduces or eliminates the risks that a con- sumer will be forced to invest in equipment with limited resale value or will be unable to use the modem after moving to a new city. The telephone industry does not have a similar uniform standard for DSL services. Wireless and Satellite Services U.S. households may also subscribe to a variety of wireless and satellite services. Unlike DSL and cable modems, most of these technologies will still take several years to develop fully and attract large numbers of subscribers. Satellite systems are the most widely used of the high-speed wireless o