The Atari 8-bit computers produce a single video signal and monophonic audio.

The 400/800 models also produce some sounds (primarily the keyclick and system
buzzer sounds) by way of an internal speaker.

Most 8-bit Atari computers put out their video and audio signals in two
places:

1) Television cable (400/800) or jack (all XL/XE but SECAM 800XL, SECAM 130XE)

This provides an analog Radio-Frequency (RF) signal carrying both video and
audio.

The Atari's RF signal may be used on a television that:
  - Supports use of an external RF antenna (normally for viewing over-the-air
    TV broadcasts)
  - Can decode an analog television signal (NTSC or PAL or SECAM, matching the
    version of the computer)
  - Has a tuner that can additionally tune to the necessary TV channel(s) used
    by the Atari

If the television has a speaker then it should support the Atari's sound
output as well.

All NTSC (North America) Atari 8-bit computers make the RF audio/video signal
available on a choice of two television frequencies, selected with a physical
switch located on the back of the computer (on the side of the 800):
  - 55.25MHz video/59.75MHz audio (TV Channel 2 in North America), or
  - 61.25MHz video/65.75Mhz audio (TV Channel 3 in North America)

PAL (Europe) Atari 400/800 computers also make the RF audio/video signal
available on a choice of two television frequencies, selected with a physical
switch located on the back of the 400, or on the side of the 800.

PAL 400/800 computers intended for use in "PAL I" countries (UK) use:
  - 607.25MHz video/613.25MHz audio (TV Channel 38 in the UK)
  - 615.25MHz video/621.25MHz audio (TV Channel 39 in the UK)

PAL 400/800 computers intended for use in "PAL B" countries (Europe) use:
  - 55.25MHz video/60.75 audio
    ` TV Channel 3 in Western Europe
    ` TV Channel 2 in Eastern Europe (approx.)
    ` TV Channel 1 in Australia (approx.)
  - 62.25MHz video/67.75MHz audio
    ` TV Channel 4 in Western Europe
    ` TV Channel 2 in Eastern Europe (approx.)
    ` TV Channel 1 in Australia (approx.)

PAL (Europe) Atari XL/XE computers make the RF audio/video signal available on
a single television frequency.

PAL XL/XE computers intended for use in "PAL I" countries (UK) use:
  - 591.25MHz video/597.25MHz audio (TV Channel 36 in the UK)

PAL XL/XE computers intended for use in "PAL B" countries (Europe) use:
  - 62.25MHz video/67.75MHz audio
    ` TV Channel 4 in Western Europe
    ` TV Channel 2 in Eastern Europe (approx.)
    ` TV Channel 1 in Australia (approx.)

SECAM (France) Atari XE Game Systems make the RF audio/video signal available
on a single television frequency:
  - 591.25MHz video/597.75MHz audio (TV Channel 36 in France)

Other than the frequency of the RF signal produced, there is no difference
between the "PAL I" and "PAL B" versions of PAL Atari computers.

If your country is not included above, Wikipedia has a nice table of
television channel frequencies used around the world that you may find
helpful for determining the channel to tune your TV to:
http://en.wikipedia.org/wiki/Television_channel_frequencies

** NOTE: MC has worked with limited reports to determine the channels used
** around the world.  I would greatly appreciate any corrections/additions to
** the information provided here!  In particular, I'm looking to verify the
** actual RF signal frequencies produced by the Atari.
** The above frequency values are only taken from the channels reported to be
** used in various countries.

Accessories needed (typical setup):
  a) RF Cable / TV Video Cable, a proprietary cable for Atari XL/XE computers
     The input end is a phono plug that plugs into the Switch Box/
     Television jack on the computer.  The output end is a phono plug that
     plugs into the TV Switch Box.

     The 400/800 models have no Switch Box/Television jack.  Instead, there is
     a cable that comes out of the back of the computer.  This cable carries
     the RF signal.  The output end is a phono plug that plugs into the TV
     Switch Box.

  b) TV Switch Box
     This includes a phono jack for RF signal input from the Atari, input
     connector(s) for your TV/cable/satellite antenna, and 75- and/or 300-ohm
     output connector(s) for connection to the antenna input on the
     television.

While the display quality of the RF video signal may be adequate, the quality
of the video provided at the Atari's Monitor port is noticeably superior.

2) Monitor port

A proprietary 5-pin DIN (SECAM: 6-pin) Monitor port, which along with the
audio signal actually provides two video signals:

  a) Composite video

  b) Y/C Video, also known as S-Video:
     separate composite luminance (Y) and chrominance (C) signals

The separate chrominance/luminance video signal is noticeably superior to both
the RF television output and the composite video output.

Monitor port exceptions among Atari computer models:
-the 400, NTSC 600XL, and XE game system lack the Monitor port.
-the SECAM 800XL and SECAM 130XE have a different, 6-pin Monitor port that
 provides composite video but not separate chrominance/luminance signals
-the XE game system includes a phono Monitor Video Jack providing the
 composite video signal, and also a phono Monitor Audio Jack providing the
 audio signal.
-The 1200XL, PAL 600XL, and 800XL(all but very late production) lack the
 separate chrominance signal at the Monitor port, and the PAL 600XL also lacks
 the separate luminance signal at the Monitor port.

Any video display monitor that supports composite video input (this generally
includes modern televisions) should be able to display the Atari's composite
video signal.  Monitors with built-in speakers for audio support, and monitors
with support for separate chrominance/luminance video inputs, are preferred
for use with the Atari.

Commodore produced many monitors with separate chrominance and luminance
inputs, making them popular with Atari users.  Lonnie McClure provides this
list of suitable Commodore monitors:

  1701, 1702, 1802, CM-141, 1080, 2002, 1902, 1902A*, 1084**, 1084S**

  * The 1902A used a DIN connector for chrominance/luminance, which makes
  cabling a bit more of a problem.  The composite and audio connectors are
  standard phono jacks, however.

  ** The 1084 and 1084S had more than one version. Some used the a DIN
  connector for chrominance/luminance connections, like the 1902A, while some
  used standard phono jacks.

  The 1902 and 1902A are very different in appearance. The original 1902
  shares the same slightly rounded front case design as the 1080 and 2002,
  while the 1902A is has a rather square case design, and was manufactured
  by Magnavox (as were some of the 1084 and 1084S versions).

The pinout for the Atari Monitor port is in the pinouts section of this FAQ
list.

The typical Atari monitor cable includes the male 5-pin DIN connector on one
end, and two phono plugs on the other end.  One of the phono plugs will carry
the monophonic sound signal, and the other will carry the composite video
signal.  Atari's own CX89 Color Monitor Cable is of this type.

You may find an Atari monitor cable where the video signal carried on the
second phono plug is not the composite video signal, but is rather the
composite luminance signal.  These cables are for use with monochrome
composite video monitors (usually green or amber).  Atari's own CX82 Black
and White Monitor Cable is of this type.

The ideal Atari monitor cable includes 4 phono plugs at the output end,
carrying the sound signal, the composite video signal, the composite
luminance signal, and the composite chrominance signal.  Only the best
composite monitors include separate chrominance and luminance inputs.  When
the separate chrominance and luminance connectors are used, the composite
video connector is not used.

There is no real standard for colors for the different monitor cable
connectors.  It is safe to identify them by trial and error.

The separate composite chrominance and luminance signals that the Atari puts
out comprise what the world has since come to call Y/C video or S-video.
S-video connectors are normally Mini4.  It is possible to build a cable, or
purchase several adapters, that can allow you to utilize the separate Y/C
signals generated by the Atari with a television (or other display device)
that provides a standard S-video Mini4 input jack.  This is the ultimate
display option for the 8-bit Atari.  Clarence Dyson has a nice page about
such a project at http://www.wolfpup.net/atarimods/svideo.html .

A "video scaler" or "up-converter" is an adapter that will accept an input
video signal such as RF, composite video, or s-video, and output a conversion
of the signal as a standard VGA video signal.  With such a device, the 8-bit
Atari can be used with a standard PC VGA monitor.  Examples:

 - AV Toolbox manufactures several suitable adapters, listed at:
   http://www.avtoolbox.com/upconpage.shtml

 - Ambery markets their "Ultra Video to VGA Converter", see:
   http://www.ambery.com/vitoxgacoscs.html
   and other suitable, more expensive Video to VGA/RGBHV Converter Scalers:
   http://www.ambery.com/vitovgcosc.html

 - Earlier popular devices included:
   - Cheese Video Box from AV Toolbox
   - JAM!! from AIMS Lab.

Some people report good results viewing the Atari computer's video signal
through a PC using a TV/video capture card.  Wikipedia's article about such
devices: http://en.wikipedia.org/wiki/Video_capture_card

SCART - an acronym for Syndicat des Constructeurs d'Appareils Radiorecepteurs
et Televiseurs - is a 21-pin universal connecting cable/socket system used for
audio/video components in Europe.  The cables transmit RGB, composite video,
S-Video, mono and stereo sound.  SCART, which is also known as PERITEL, EURO
AV BUS and EUROCONECTOR, is common throughout Europe, particularly in France,
England, Germany, Switzerland, and Scandinavia.  SCART is also very popular in
the Russian Audio Video market.  It is possible to interface the Atari's
composite video signal, along with the audio signal.  DGS sells such a cable,
see: http://www.dgs.clara.net/

Two current sources for Atari monitor connectivity products:
  More Than Games produces "A8 A/V BOB", an audio/video breakout box featuring
  phono jacks for composite video, chrominance, luminance, and mono audio; it
  also features an s-video jack providing chrominance and luminance.
  http://morethangames.a8maestro.com/proda8/adv-eh0101.htm

  Vintage Computer Cables produces Atari monitor cables designed for use with
  televisions, plus an Atari S-Video cable.
  http://www.vintagecomputercables.com/