Video Interfaces
Video Interfaces
You should be familiar with the following video interfaces.
Interface
Description
D-sub
Cable
The D-sub connector, sometimes called a VGA connector, uses a DB-15
connector with three rows of pins. The D-sub connector on a video card
provides analog output. You can connect the following monitors to a video
card with a D-sub connector:
Analog CRT monitor.
LCD monitor that accepts an analog connection. Some LCD monitors
have a D-sub connection, or you might need a cable with a D-sub
connection on one end and a DVI-A connection on the other end to
connect to the LCD monitor.
Female port
DVI-A
Cable
A DVI-A (digital video-analog) connection on a video card provides analog
output. DVI-A connections are rarely (if ever) used for computers monitors,
but might be used on some HDTV systems. You can connect the following
monitors to a video card with a DVI-A connector:
DVI-D
A DVI-D (digital video-digital) connection on a video card provides digital
output. DVI-D connections are rated as either single link or dual link:
Single link cable
Dual link cable
Female port
Analog CRT monitor. Use a cable with a D-sub connection on one
end and a DVI-A connection on the other end to connect to the
monitor.
LCD monitor that accepts an analog connection. Some LCD monitors
have either a D-sub or a DVI-A connection.
Single link connectors have 3 rows of 6 pins with one additional
larger horizontal pin. Single link can support 60 Hz up to 1920x1080
resolution.
Dual link connectors have 3 rows of 8 pins plus the horizontal pin
(often called a 25-pin, 24+1-pin, or 24-pin connector). Dual link can
support 60 Hz up to 2048x1536 resolution.
Dual link allows for longer cable lengths and a higher video resolution.
When choosing a video card, choose a card that supports dual link
whenever possible.
You can only connect a digital monitor to a DVI-D connector. Connecting an
analog monitor, such as a CRT monitor, is only possible by using a special
converter box. If the video card only has a DVI-D connector and you have
an analog-only monitor, it is often cheaper to purchase a new video card
instead of the converter box.
Note: CRT monitors with DVI-D connectors are possible but rare. This
means that the CRT monitor accepts digital input.
DVI-I
A DVI-I (digital video-integrated) connection on a video card provides both
analog and digital output. The DVI-I connection has all of the pins present in
both the DVI-A and DVI-D connections. Most video cards and many LCD
monitors have a DVI-I connection. You can connect the following monitors
to a video card with a DVI-I connector:
Video Interfaces
Single link cable
Analog CRT or LCD monitor using a cable with a D-sub connection
on one end and a DVI-A connection on the other end.
LCD monitor with either a DVI-I or DVI-D connection.
Dual link cable
Female port
DMS-59
The DMS-59 connector is used to allow multiple video ports from a single
connection. The DMS-59 connector:
Female port
Composite video
Cable
A composite video connection on a video card provides analog, video-only
TV output. Composite video connectors are RCA connectors (typically
yellow). Composite signals combine three qualities of video into a single
signal:
Female port
S-video
Is typically included on slimline video cards that can have only a
single port.
Sends out two separate DVI-I signals through the single connector.
Uses a special cable that splits the signal into separate video
interfaces. For example, the cable might split the signal into two DVI-I
connectors, two D-sub connectors, or one DVI-I connector and one
D-sub connector.
The Y channel is for brightness or luminance
U and V channels provide color information
Use the composite connection to connect a TV, VCR, or video camera to
the video card. Audio signals must be supplied separately.
S-video (separate-video, Y/C, or S-VHS) connections are present on many
video cards and supply analog, video-only TV output. The s-video connector
is a 4-pin mini-din connector that has two separate channels, one for Y
(luminance) and one for UV (color). S-video can easily be converted to
composite video by combining the Y and UV channels into a single signal.
Cable
Female port
HDTV (Component)
Female port
HDMI
Cable connector
An HDTV connector supplies analog, video-only TV output in three separate
channels: R (red), G (green), and B (blue). The HDTV connector uses a 7pin mini-din cable. Video cards with HDTV output typically include a
conversion cable that converts the 7-pin connector into three RCA cables for
connecting to an HDTV device. As with composite and s-video, audio must
be supplied to the device separately.
High-Definition Multimedia Interface (HDMI) is a digital video and audio
connector used for high-definition digital audio and video. HDMI combines
the audio and video signals onto a single cable. You might use HDMI
connectors in the following configurations:
You can use a DVI-to-HDMI cable to connect the DVI-D output from a
video card to a monitor or an HDTV device that has an HDMI
Video Interfaces
connector. However, this configuration only supplies video, and not
audio, to the display device.
You can purchase a video card with an HDMI connector. Many of
these video cards have an audio input port that accepts digital audio
into the video card where the audio signals are combined with the
video signals and sent out the HDMI port. In this configuration, the
video card does not process the audio, but simply passes it through
the video card from the external source and onto the HDMI output.
Cable TV (BNC)
Video cards and monitors with a built-in TV tuner have a BNC cable TV
connector. Most video cards that provide cable TV input also include audio
output. However, most of these cards do not provide analog or digital
monitor output.
Cable
Note: Do not confuse video in, which can be supplied by composite, svideo, or HDTV connectors, with TV-tuner capabilities. The built-in tuner
means that the card or monitor itself has the ability to accept multi-channel
input and change the display by changing the channel. Without a built-in
tuner, video input is limited to a single channel, and changing TV channels
must be done at the source device before inputting into the video card.
Female port
Note: When connecting various devices to a computer video card, you can typically find converter cables to
match the interface on the video card with the interface on the device. However, these cables do not convert from
analog to digital signaling.