Audio & Video Cables and their connectors may seem simple enough, however for the novice when you begin shopping around you can quickly discover that they vary greatly in purpose, price, and quality. This guide will hopefully help you to identify some of the most common types of cables and their connectors, and understand some of the terminology used to describe them.
3.5mm and 6.35mm Connectors
The most common audio cable is the standard headphone jack. It is available in several sizes, but the most common ones used with computers is the 3.5mm mini audio jack. Also referred to as an audio jack, stereo plug, jack plug, mini-jack, mini-stereo, or headphone jack and is a common analogue audio connector.
Also known as a TRS connector (tip, ring, and sleeve) which is derived from the names of the conducting parts of the plug and is cylindrical in shape, typically with three contacts, although sometimes with two (a TS connector) or four (a TRRS connector).
(1), TIP: - Left-hand channel for stereo signals, positive phase for balanced mono signals, signal line for unbalanced mono signals
[2), RING: - Right-hand channel for stereo signals, negative phase for balanced mono signals, power supply for power-requiring mono signal sources
(3), SLEEVE: - Usually ground
(4), INSULATING RINGS
Originally invented in the 20th century for use in telephone switchboards and is still widely used today. The most popular sizes used are the 6.35mm (1/4”) and in its smaller versions 3.5 mm (1/8”) and 2.5mm (3/32”). In the UK, the term jack plug and jack socket are commonly used to refer to the gender of the respectively male and female TRS connectors.
The most common arrangement still remains today whereby the male plug is on the cable and the female socket is mounted on the hardware and is the original intention of the design.
Most speakers and microphones can connect to the computer with these audio cables. The microphone (input) port on your computer is usually pink while the speaker (output) port, where you insert the stereo audio cable, is coloured green. Some computers have additional TRS audio ports coloured black, grey, and gold; these are for rear, front, and centre/subwoofer output, respectively.
An RCA connector, sometimes called a phono connector or cinch connector, is commonly used to carry audio and video signals. The name "RCA" derives from the Radio Corporation of America, which introduced the design in the early 1940s. The connection's plug is called an RCA plug or phono plug, for "phonograph". The name "phono plug" is sometimes confused with a "phone plug" which refers to a TRS connector plug.
The RCA phono cable has a variety of uses to include but not limited to the provision of left and right audio signals when connecting DVD players, set-top boxes etc to a TV or AV amplifier. A single RCA cable can be used for digital coaxial or subwoofer connections. A twin RCA is commonly used for left and right stereo audio connections.
TOSLink is a standardized optical fibre connection system. Its most common use is in consumer audio equipment (via a "digital optical" socket), where it carries a digital audio stream between components such as AV Amplifiers, DVD players, MiniDisc, CD players, desktop computers etc. Designed for high end audio where you need to connect the output from a DVD player or set-top box to a home theatre system. These fibre optic cables can transmit pure digital audio through light. Some laptops and audio equipment have a mini-TOSLink jack but you can use a converter to connect it to a standard TOSLink port.
Video Cables are available as either analogue or digital interconnects, with the majority of analogue video interconnects being based on the same type of RCA connectors found in home theatre sound systems.
Although most analogue video cables use the same end-connectors found on audio cables, this does not imply that audio cables can replace video interconnects.
The use of double shielded interconnects using both braided copper and metal foil, with high quality 'silver-plated' inner conductors and 'gold-plated end connectors', is almost a pre-requisite in quality video cables to preserve the strength and accuracy of the original video signal.
A composite video connection is a direct video connection using an RCA connection. It is a very common method for connecting a variety of devices. For most home applications the composite video signal is typically connected using an RCA phono plug. The connectors are often colour-coded, yellow for composite video, red for the right audio channel and white or black for the left audio channel of stereo audio.
This trio (or pair) of jacks can be found on the back of almost all audio and video equipment. At least one set is usually found on the front panel of modern TV sets, to facilitate connection of camcorders, digital cameras, and video games consoles. In most cases, composite video cables are sold bundled with a pair of stereo audio cables for convenience. It’s superior to the RF type of connection but inferior to S-Video and Component Video.
Separate Video, more commonly known as S-Video, is an analogue video signal that carries video data as two separate signals: luma (luminance) and chroma (colour). This differs from composite video, which carries picture information as a single lower-quality signal, and component video, which carries picture information as three separate higher quality signals. S-Video carries standard definition video, but does not carry audio on the same cable.
An S-Video signal is generally connected using a cable with 4-pin mini-DIN connectors. Due to the wide use of S-Video connections, they are fairly inexpensive compared to component or digital connector cables.
S-Video is commonly used throughout the world with relative popularity. It is found on consumer TVs, DVD players, high-end video cassette recorders, digital TV receivers, video recorders, game consoles, and graphics cards. It has been replaced by component video and digital video standards, such as DVI and HDMI.
Component video provides a better picture quality than composite because the video signal that has been split into two or more components, while in the case of composite; everything is transferred through a single yellow plug. Like composite video, component video cables do not carry audio and are often paired with audio cables.
Component video is capable of carrying signals such as 480i, 480p, 576i, 576p, 720p, 1080i and 1080p. The new high definition TVs support the use of component video up to their native resolution. Although component video is inferior to the digital connections of DVI and HDMI, component video is superior to both S-Video and Composite video because it provides improved colour purity, superior colour detail, and a reduction in colour noise.
A possible source of confusion is that the word component differs from composite (an older, more widely-known video format) by just a few letters. Component video connectors are not unique in that the same connectors are used for several different standards; hence, making a component video connection often does not lead to a satisfactory video signal being transferred.
The settings on many DVD players and TVs may need to be set to indicate the type of input/output being used, and if set incorrectly the image may not be properly displayed. Progressive scan, for example, is often not enabled by default, even when component video output is selected.
Modern game systems (such as the PlayStation 3, Xbox 360, and Wii) use the same connector pins for both YPbPr and composite video, with a software or hardware switch to determine which signal is generated. Hence, a common complaint is that the component video signals are very green, with very dark reds and blues. This is simply because the system menu has not been changed from AV (composite) to RGB (component).
The Digital Visual Interface (DVI) is a popular form of video interface designed to provide a very high visual quality on digital display devices such as flat panel LCD computer displays, computer graphics cards and digital projectors. DVI cables are becoming increasingly popular with video card manufacturers, and most cards nowadays include both a DVI and a VGA output port. It carries uncompressed digital video data to a display and is partially compatible with HDMI in digital mode (DVI-D), and VGA in analogue mode (DVI-A), so a simple gender changer will allow a DVI monitor to receive input from an HDMI cable. Additionally, DVI to VGA gender changers are also available to connect your new graphics card to an older style monitor that supports VGA mode only.
However DVI does not support audio signals, so a separate audio cable may be required. If you have recently purchased a new desktop computer or laptop, there's a good possibility that it may have DVI connector instead of VGA or it may even have both. A DVI cable can have up to 29 pins, although some DVI connectors may have less pins than this depending on the connector type. The long flat pin on a DVI-I connector is wider than the same pin on a DVI-D connector, so it is not possible to connect a male DVI-I to a female DVI-D by removing the 4 analogue pins. It is possible, however, to connect a male DVI-D cable to a female DVI-I connector. Many flat panel LCD monitors have only the DVI-D connection so that a DVI-D male to DVI-D male cable will suffice when connecting the monitor to a computer's DVI-I female connector.
The DVI-I Single Link Connector is an integrated analogue and digital DVI connector that is compatible with VGA and with digital video cards. With a single DVI link, the largest resolution possible at 60 Hz is 2.75 megapixels (including blanking interval). For practical purposes, this allows a maximum screen resolution at 60 Hz of 1915 x 1436 pixels (standard 4:3 ratio), 1854 x 1483 pixels (5:4 ratio) or 2098 x 1311 (widescreen 8:5 ratio).
The DVI-I Dual Link Connector has provision for a second link, containing another set of red, green, and blue twisted pairs. When more bandwidth is required than is possible with a single link, the second link is enabled, and alternate pixels may be transmitted on each, allowing resolutions up to 4 megapixels at 60 Hz. The DVI specification mandates a fixed single link maximum pixel clock frequency of 165 MHz, where all display modes that require less than this must use single link mode, and all those that require more must switch to dual link mode. When both links are in use, the pixel rate on each may exceed 165 MHz. The second link can also be used when more than 24 bits per pixel is required, in which case it carries the least significant bits.
The DVI-D Single Link Connector is a digital only DVI connector. With a single DVI link, the largest resolution possible at 60 Hz is 2.75 megapixels (including blanking interval). For practical purposes, this allows a maximum screen resolution at 60 Hz of 1915 x 1436 pixels (standard 4:3 ratio), 1854 x 1483 pixels (5:4 ratio) or 2098 x 1311 (widescreen 8:5 ratio).
The DVI-D Dual Link Connector has provision for a second link, containing another set of red, green, and blue twisted pairs. When more bandwidth is required than is possible with a single link, the second link is enabled, and alternate pixels may be transmitted on each, allowing resolutions up to 4 megapixels at 60 Hz. The DVI specification mandates a fixed single link maximum pixel clock frequency of 165 MHz, where all display modes that require less than this must use single link mode, and all those that require more must switch to dual link mode. When both links are in use, the pixel rate on each may exceed 165 MHz. The second link can also be used when more than 24 bits per pixel is required, in which case it carries the least significant bits.
The DVI-A Connector is an analogue only DVI connector that is compatible with VGA. The Digital Visual Interface (DVI) is a video connector designed to maximize the visual quality of digital display devices such as flat panel LCD computer displays and digital projectors.
Some new DVD players, TV sets (including HDTV sets) and video projectors have DVI/HDCP connectors; these are physically the same as DVI connectors but transmit an encrypted signal using the HDCP protocol for copy protection.
DisplayPort is a combined digital interface cable which can support both digital video and audio. It's primarily used between a computer and its display monitor or a computer and a home cinema system. The smaller derivative, the Mini DisplayPort connector is currently used in MacBooks but we could see them in other computer systems as well in the near future. Both types of connector support resolutions up to 2560 × 1600 × 60 Hz.
Standard DisplayPort cables can be up to 3 meters long for maximum resolution, but at a lower resolution cables can be up to 15 meters long. DisplayPort connectors are available to connect VGA, DVI video, or HDMI video and audio with a DisplayPort cable or connection. Additionally, converters are available to convert Mini DisplayPort into standard DisplayPort.
In January 2008, Dell released the first monitor to support DisplayPort, the Dell 3008WFP 30-inch (76 cm), which was shortly followed in April 2008 by the Dell 2408WFP 24-inch (61 cm). In 2009, some graphic card manufacturers started including DisplayPort on their graphic cards. Other companies have announced their intention to eventually implement or support DisplayPort which includes; Acer, AMD/ATI, Apple, ASRock, Dell, Fujitsu, Gigabyte Technology, Hewlett-Packard, Intel, Lenovo, Matrox Graphics, NEC, NVIDIA, Philips, S3 Graphics and Toshiba to name a few.
High-Definition Multimedia Interface is an audio/video interface for transmitting uncompressed digital data. It carries both audio and video signals via a single compact cable. It is an alternative to composite video, S-Video, SCART, component video, or VGA.
HDMI connects a variety of digital audio/video devices such as set-top boxes, Blu-ray disc players, personal computers, video game consoles (such as the PlayStation 3 and some models of Xbox 360) and AV receivers to compatible digital audio devices, computer monitors, and digital televisions. HDMI can support a maximum resolution of 4096×2160p (HD is only 1920×1200) with up to 8 channels of digital audio.
HDMI cable lengths can be up to 15-20 meters long which can be further increased with the use of an extender. Because HDMI is electrically compatible with the signals used by DVI, no signal conversion is necessary, nor is there a loss of video quality when a DVI-to-HDMI adapter is used, though you will have to use a separate cable for the audio.