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Video Output

Video output comes in various types of connectors based on the motherboard’s chipset or the graphics card’s chipset. The standard that has been used for the past few decades is the VGA (video graphics adapter), which is a DB-15 style connector. VGA relies on providing a good-quality analog output to a traditional computer monitor. The port for this connector is the blue one on the left in the image below.

Blue VGA connector, white DVI connector, and black HDMI type A video connector. Photo used under CC-BY license from Davis Mosans.

The next connector port, shown in white in the middle of the photo above, is called DVI, or digital video interface. It comes in DVI-D (for digital output only), or DVI-I (for integrated output that can provide digital or analog output) varieties. A DVI-I connector can be used with an adapter to operate with a traditional VGA monitor in analog mode, as well.

The third connector, shown on the right of the image, is an HDMI, or high-definition multimedia interface, connection. HDMI comes with three standard connector types: type A (standard), C (mini), and D (micro). Although there is a designation for a type B, it has not been adopted by any manufacturers at this time. Version 2.0 supports 4K UHD and HDR-enabled devices. Micro HDMI has been largely adopted by the mobile telephone market and is included on almost all current models. The special thing about HDMI is that it isn’t limited to carrying just video, but instead carries both audio and video over a single HDMI cable. HDMI is fully digital and doesn’t support analog displays.

Another connector is DisplayPort, which has two form factors, as shown in the images below. DisplayPort was designed by the Video Electronics Standards Association (VESA). Mini DisplayPort was a standard announced by Apple in 2008 and adopted by VESA in 2009 to be included in version 1.2 (https://en.wikipedia.org/wiki/DisplayPort#1.2).

This makes it an ideal interface connector for laptops and mobile devices, similar to HDMI mini. It is also similar to HDMI in that it supports both video and audio with resolutions up to 3840x2160, which can support 4K UHD. DisplayPort can be found on IBM-clone (PC) machines and is gaining traction in the marketplace on mobile devices as well.

DisplayPort. Photo used under CC-BY license from Wirepath (Yoe).

Mini DisplayPort. Photo used under CC-BY-SA license from William Hook.

Component/RGB (red green blue) is another high-definition connector type, but provides its output in analog format and only up to 720p of resolution. This was commonly used by VCR and DVD players, to connect to television sets, but can sometimes be found on older computers as a secondary output connector. Using RCA connectors, component video actually requires three connectors to pass the video signal to the TV, each one with a different colored label of red, green, and blue. Audio signals require separate patch cords.

Component/RGB. Photo used under CC-BY-SA license from Wikipedia.

S-video is a very old type of connection that was originally used to connect video cameras and VCRs to televisions. They provide a resolution of up to 480p in analog signal only. They are often labeled as “TV out” on older computer systems, and are used only as a secondary display output.

S-video connection. Photo used under CC-BY-NC-ND license from yum 9 me.

Finally, we have the oldest type of video interface, Composite Video. This is by far the lowest quality output of all the types we have discussed. This cable also uses RCA connectors with an output of 480p. This cable combines all the video signals over a single RCA cable, usually labeled as “video,” and the connector itself is yellow. The Composite Video cable operates in analog signal only with the audio signal separate as well. Composite differs from Component in that audio cable are bundled together with the Composite Video (Red, White, Yellow), whereas, Component uses a total of five cables (Red, Green, Blue for video and the standard Red and White for audio).

Composite video RCA cable connector. Photo used under CC-BY-NC license from Dani Armengol Garreta.

As we discussed in a previous module, storage is one function that makes a computer a computer. So, storage devices are a critical component. Storage devices hold all of the bits and bytes that make up the data we process, photographs, music, and more. There are many different types of storage devices used with modern computers, including hard drives, optical drives, and external drives. Some computers still have legacy storage devices such as floppy disks.

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