CATV originally stood for Community Access Television but is now more commonly known as Cable TV. CATV is one of the most common methods of transmitted television signals to a consumer's home, using radio frequency signals transmitted through coaxial cable. More recently, CATV can also transmit over optical fiber, which utilizes pulses of light to send and receive signals.
CATV origins date back to 1924 when some cable broadcasting was done using cable in European cities. In 1948, community antennas were built where over-the-air signal reception was limited. The community antenna received the over-the-air signal and then transmitted it to households by cable. Today, CATV offers analog and digital channels (including high definition). Receiving digital channels requires a cable box for conversion.
CATV should not be used to describe Cat 5 networking or cable.