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 be transmitted using optical fiber, which utilizes pulses of light to transmit a signal.
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.