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TV as explained to the computer generation...

Slashdot | Confusion Reigns As Analog TV Begins Shutdown

A TV (or television) is like a computer monitor, except that it doesn’t need to be plugged into a computer to display a video signal. It uses a radio link to connect to a wireless access point, kind of like bluetooth or wifi, except the link is only one way, and the access point may be many kilometres away. In fact, the same signal is sent to many TVs simultaneously, in much the same way that a broadcast frame is seen by all of the computers on a LAN. They actually call the television signal a “broadcast”. Everybody sees the same stream at the same time. TVs have no facility to back up and replay the video stream. It cannot be paused, either.

Since the wireless link is a simplex link, everyone is stuck receiving the same video signal. A TV viewer is bound by the scheduling and content choices made by a person called a program director who works at the broadcast facility. In order to alleviate this obvious problem, “channels” were introduced. Each channel streams a different video stream. However, due to the expense of the transmitting equipment and the fact that they are all using the same transmission medium (the so called aether), only a handful of channels exist. Until recently, these video streams were transmitted using an analog signal. As such they were plagued with interference, crosstalk, etc.

To combat these obvious defficiencies, many places started streaming the video to the TV over a shared wire. This eliminated most of the interference issues, and allowed for more video stream channels to be sent to the television. Over time, the TVs became more like computers. The monitor was connected to a box which contained a hard drive, allowing video streams to be recorded and played on demand. The signals were transmitted digitally, which allowed for error correction, and it allowed for true internet connectivity and two way communication. Most people still use them only for simple video streaming, however. There are also quite a few people who (probably for quaint religeous reasons), still rely on the analog wireless broadcasts to receive their pre-scheduled, pre-chosen video stream.