An alternative method to broadcasting television over the airwaves carries TV signals over insulated copper coaxial cable into stations and homes. There were experimental coaxial lines as early as the 1930s, but by the 1940s, some regular lines had been laid. They were used for phone and television, and they were ideal for getting TV out to rural areas that were hard to reach via broadcast towers. Early coax could only carry one television program -- or 480 phone conversations -- at a time, but by the 1970s, those numbers reached 200 programs and 132,000 phone calls [source: FCC]. Also in the 1970s, fiber optic cable made of plastic or glass was invented that carried much more data at a faster rate than copper. Both are used now to provide consumers with ever-increasing cable, phone and Internet bandwidth.
And from this technology, the multichannel video programming distributors (MVPD) that bring millions of U.S. homes their television via this method took their name: cable TV. This incarnation of cable led to an incredible boom in the amount of available television content. It's a pay service that offers far more channel choices than the traditional broadcast networks, and the number of channels just seems to grow and grow. This has changed our viewing habits drastically. In its early days, cable TV was relatively free from commercials, but now most channels have morphed into something more similar to the traditional networks. There are premium and mostly commercial-free channels that you can get for additional subscription fees.
As of the third quarter of 2011, roughly 90 percent of households that watched TV got it through a subscription to either cable or its phone company and satellite competitors [source: Nielsen]. Relatively few relied solely on broadcast TV anymore.