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ANALOG VERSUS DIGITAL: THE DIFFERENT TYPES OF AUDIO AND VIDEO CONNECTIONS.
 ANALOG VIDEO
On the video side, the types of analog cables are a follows.
Coax: Coax is a 75 coaxial (two conduits that share the same axis. One wraps around the other) cable with F type (screw on) connectors at the end. This type of cable contains both audio and video signals and is carried in a radio frequency (RF) form. It is only capable of standard definition, broadcast quality display (480i).
Composite:  This is also a coax cable but with RCA connectors on each end. The connectors are usually color coded yellow. It is a single cable that only carries the video signal. It is called composite because it is a composite (blend) of all the video signal information (color, brightness and sync). It is often paired with red and white RCA audio cables. It is only capable of standard definition (480i).
S-Video: Stands for Separate video. Also sometimes referred to as S-VHS. It is a 4 pin mini din connector. It does not carry audio and separates out the components of the video signal into Chrominance (C) and Luminance (Y), also known as color and brightness, along the 4 pins. It is only capable of standard definition (480i).
Component: Component most often refers to the connection of 3 RCA connectors that are color coded red, green and blue and carries a Y, Pr, Pb or Y, Cr, Cb signal. It is called Component because the signal is broken into the 3 primary color components of the video signal. In the 3 connector component the sync information is carried on Green (Y). Sometimes, 5 BNC connector cables are also referred to as Component Video. However, this type of connection further breaks down the components of the video signal into Red, Green, Blue, Horizontal sync and Vertical Sync (RGBHV) like VGA. Component is capable of standard and high definition resolutions from 480i to 1080p.
VGA: Stands for Video Graphics Array. It uses a 15 pin (HD15) connector. It breaks the signal down to Red, Green, Blue, Horizontal sync and Vertical Sync (RGBHV) with other components for calibrating the display. It is most often found on analog computer displays. Although VGA specifically means a resolution of 640 X 480, VGA and SVGA cables and connectors are actually capable and are used for much higher resolutions. The difference between VGA and SVGA cables would be the bandwidth that the cable is capable of carrying. The S in SVGA stands for Super.
Basically, each subsequent development of analog cable technology is much better than the technology that preceded it with Component and VGA being the best type of connection in terms of picture quality.
DIGITAL VIDEO
On the Digital side we have the following:
DVI: Stands for Digital Visual Interface. DVI actually has several different types of connectors each with different abilities. More information can be found on our article regarding DVI.
HDMI: Stands for High Definition Multimedia Interface. It is the newest format for digital video and carries both audio and video signals. More details are available in our article about HDMI.
When it comes to Digital Video, HDMI is DVI in a different form. It is not superior or inferior to DVI in terms of picture quality. And, in most respects is on par with its counter parts on the analog end, Component and VGA.
AUDIO
On the audio side we have the following:
RF: Radio frequency, which is basically the type of audio you get from an FM radio. It is they type usually transmitted over the air (OTA) or through coax cables with F type connectors.
Analog Stereo: These are connected using 2 RCA coaxial stereo cables. They carry two channel stereo sound which can be separated into 4 channels or more using Dolby Surround or Dolby Prologic processors.
Digital Coax: Digital Coax uses a standard 75 ohm coax cable with RCA connectors. It is often color coded orange. It transmits a S/PDIF (Sony/Philips Digital Interface Format) digital signal in electronic form. S/PDIF is a compressed digital format. It is capable of 5.1 channels or more of audio and processed by formats such as Dolby Digital and DTS.
Digital Optical (Toslink): Digital Optical uses a fiber optic cable with Toslink connectors on the ends. It transmits S/PDIF digital signal in the form of red light. It is the same type of signal as the one used by digital coax but because it is in a different form, light versus electric, they are not interchangeable without conversion. It is also capable of 5.1 channel or more of audio as well.
Multi-Channel, High Resolution Analog Audio: Due to the limitation of compressed digital audio (compression throws out the highest and lowest frequencies in a given sample of audio), when developers of high resolution, multi-channel audio formats such as DVD-Audio and SACD, created their disc players, they went back to coaxial analog cables in order to transmit the full range of frequencies on their media. They had to use one cable for each channel of information. Therefore, this type of connection is usually a bundle of 6 cables with 6 RCA connectors on each end, one for each of the 5.1 channels of audio. Some equipment may use more.
HDMI Audio: HDMI promises 7.1 channels of high resolution, uncompressed digital audio. This means that it can take the high resolution audio of formats like DVD-Audio and SACD and transmit it through a single cable. However, not all receivers are currently able to process HDMI audio and concerns still exist regarding the level of jitter and noise in the HDMI bitstream.
On the audio side, the superiority of one format over the other is not clear cut. Though most other types are better than RF, an argument can be made for each of the remaining types of connections. For instance, some audiophiles will insist that analog connections will always be superior to anything digital because audio is analog in nature. There are a few other types of connectors as well, but these are the main ones.
One other type of audio cable is the LFE (Low Frequency Effects) or Subwoofer cable. It is used to connect a powered subwoofer to the pre amp subwoofer output on the back of a receiver. It is actually a simple 75 ohm coax cable that is also used for analog audio, video and digital audio. Some cable manufacturers produce special LFE cables that are specifically calibrated to efficiently carry only the Lower frequencies used by a Sub. However, many manufacturers of high end Subs will specifically recommend using full frequency cables so that you do not loose any of the sonic details that the subwoofer is capable of producing. HotwireCables.com Subwoofer/Digital Audio cables are full frequency and can serve multiple functions each to its maximum potential.
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