The Different Types Video Interfaces
The modern day PC comes with a variety of Video Interfaces. The information on this page will help you decide which Interface will best suit your needs
The D-Sub (DB-15)
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.
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:
- 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.
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 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.
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
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:
- 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.
The DMS-59 connector is used to allow multiple video ports from a single connection. The DMS-59 connector:
- 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.
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:
- 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.
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 7-pin 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 connector. However, this configuration only supplies video, and not audio, to the display device. (DVI and HDMI are electrically equivalent, meaning that a simple pin-to-pin adapter is all that is required to connect a DVI device to an HDMI port.)
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.
There are actually four different HDMI connector types, but the one shown is the most common.
DisplayPort is an alternative to an HDMI connector.
DisplayPort uses a different signal format than DVI or HDMI. However, DisplayPort supports sending DVI or HDMI signals over the same port using a simple adapter.
DisplayPort uses a digital-only signal. To connect a VGA monitor to a DisplayPort, you will need a special active converter that reformats the signal for analog devices.
Like HDMI, DisplayPort can send audio signals over the same cable (if audio is supported by the video card and monitor).
DisplayPort uses lower voltage than DVI and HDMI.
DisplayPort is also an internal video interface used by laptop displays to interface with internal video cards.
For manufacturers, the DisplayPort is royalty free, whereas including an HDMI connector requires a fee for each connector used. Manufacturers such as Dell and Apple are starting to use DisplayPorts in monitors and video cards, but DisplayPorts are not yet used on HDTV sets.
Cable TV (F-type)
Video cards and monitors with a built-in TV tuner have an F-type 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.
Do not confuse video in, which can be supplied by composite, s-video, 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.
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.