Audio and video connections explained

Scart, HDMI, Coaxial are just a few of the connections found on consumer electronics devices like TVs and DVD players. What do they mean and what do they all do?

If you’ve ever looked around the back your television at the array of ports and cables and wondered what everything does, you are not the alone. The sheer number of connections in different shapes and sizes can be baffling and intimidating.

Many homes now have a flat-screen television, set-top box, DVD player or Blu-ray player - and they are all connected together by some form of cable. 

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Here’s a guide of what each of the major A/V connections does and what devices you’ll find them on.

Many ports fulfil the same functions, so it’s likely you won’t use them all at once, but the back of your electrical devices should be less confusing.

HDMI cable

What is HDMI? 

HDMI (High Definition Multimedia Interface) ports are found on the majority of home electronics appliances.

It’s a digital connection used for transferring high definition picture and sound, including surround sound.

It has a Consumer Electronics Control (CEC) channel, which handles two-way control, such as automatically turning your TV on when you turn your Blu-ray player on.

Found on: HDTVs, set-top boxes, games consoles, Blu-ray players.

What is Mini HDMI?

Exactly the same as full size, but smaller dimensions mean you find it on portable devices.

Found on: Digital cameras and camcorders.

MHL cable

What is MHL?

MHL (Mobile High Definition Link) is used for transferring HD video and audio from portable devices like a mobile phone, to HD-ready AV equipment such as a HD television or A/V receiver.

It can also be used for charging.

Found on: Smartphones, tablets.

Scart cable

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What is Scart?

21-pin connector for carrying stereo sound, video and limited control between A/V devices, such as a TV or DVD player.

Scart, which stands for Syndicat des Constructeurs d'Appareils Radiorécepteurs et Téléviseurs after the French organisation that designed the connector as far back as 1970, is an analogue connection and only supports standard definition, so it has been usurped in popularity by HDMI.

Found on: Televisions, HDTVs, DVD Players, Blu-ray players, set-top boxes.

Component AV cable

What is Component AV?

Used for carrying an analogue video signal. The video signal is split into three, so component cables consist of a trio of red, green and blue cables.

Audio is carried via two further cables, for left and right stereo channels.

Component AV supports standard definition and high definition signals, but isn’t as convenient as HDMI.

Picture quality is superior to other analogue connectors.

Found on: HD TVs, DVD players, Blu-ray players.

S-Video cable

What is S-Video?

A single jack used for carrying standard definition analogue video signals.

It comprises of two pairs of pins. One carries brightness (luma) and one carries colour (chroma).

Found on: HD TVs, DVD players, Blu-ray players.

Composite AV cable

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What is Composite AV?

Composite connections comprise of three cables. A single yellow cable for carrying an analogue picture and (like component) two further cables, for left and right stereo channels.

Found on: HD TVs, DVD players, Blu-ray players.

Optical out cable

What is Optical out?

Used for transmitting audio. It can carry digital stereo or surround sound.

Optical sends audio as a beam of light, which in theory means no loss of signal.

It is typically used within a surround sound system for connecting a Blu-ray player to an A/V receiver.

Found on: HD TVs, DVD players, Blu-ray players, Games consoles.

Coaxial cable

What is coaxial?

Used for transmitting audio. It’s can carry digital stereo or surround sound.

Unlike optical out the signal is sent down a regular piece of wire as an electricial signal, meaning (unlike Optical out) some loss of signal strength could occur over longer distances.

Found on: HD TVs, DVD players, Blu-ray players.

Audio out cable

What is Audio out?

Left and right jacks used for sending stereo audio.

Found on: HD TVs, DVD players, Blu-ray players

Ethernet cable

What is Ethernet?

Used for connecting devices to the internet.

These are increasingly found in home entertainment devices, such as the YouView box for accessing On Demand and Catch Up shows.

Found on:  Computers, set-top boxes, laptops, HDTVs.

3.5mm jack cable

What is a 3.5mm jack?

Used for transferring an audio signal between two devices. 

The majority of smartphones, laptops and laptops include a 3.5mm jack for plugging in headphones or a microphone.

The port can also be used for a connecting a mobile phone to a speaker to play back music.

Found on: Smartphones, tablets, laptops, PCs, speakers.

VGA cable

What is VGA?

Typically found on computers, VGA (Video Graphics Array) is used for carrying analogue video signals.

Found on: PCs, old-style CRT televisions and HDTVs.

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