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Connecting it all up

Why are there so many sorts of connecting cables? Find out with this quick guide.

Why are there so many sorts of connecting cables?  Find out wit
published on UK Free TV

Why are there so many sorts of connecting cables? Find out with this quick guide.

The connectors on each cable are called plugs (and are also called male) and they will usually fit only into one sort of socket (or female connector).

Most cables you will come across are male to male. Occasionally you will find leads with a socket on one end and a plug on the other, and these are called "extension cables".


The SCART cable is used to connect a set-top box to a television set, or to a video recorder. This can only be a short cable. The SCART cable carries all of these types of signal:

  • analogue stereo sound
  • a single RGB television picture
  • a single composite video picture
  • a single S-Video video picture
  • widescreen picture signal

As stereo sound, RGB picture and widescreen signal is the best possible combination for digital television viewing, it is vital to use a SCART lead between any set-top box and the main television.

The composite video picture with stereo sound is the best combination for a VHS video recorder. If your set-top box has two SCART sockets, it is likely that the one marked TV will carry RGB picture information and the other will not.

If your television has more than one SCART input, you may need to choose a special one (marked RGB) if you want to use RGB from the SCART cable.

On most set-top boxes it is possible to turn the RGB output on and off. This can be used to test the RGB input function on the television ? the picture quality appears blurred when it is disabled.

If have a DVD player, rather than a VHS recorder, you can attach this to the set-top boxes second SCART connector. The signal from the set-top box will normally be overridden by the DVD player when it is on, usually in high-quality RGB.

Some very cheap SCART cables do not have all the pins connected. They may not provide RGB and widescreen picture signals. SCART cables are normally no more than three metres in length.

UHF lead

The UHF lead is a lead that you would traditionally associate with television signals. They can carry:

  • up to 45 (but normally only five) analogue television channels
  • a single picture from a set-top box
  • around 50 analogue cable TV channels
  • mono sound
  • NICAM stereo sound
  • Teletext services (for example, Ceefax)

You can't avoid these cables if you are going to use Freeview, as these cables are the only ones that you can use to distribute Freeview signals around the house.

Where you have an integrated digital television (an idTV) you just need to get the signal from the aerial to the television with one of these cables.

If you are using a Freeview set-top box, you will need to get the signal from the aerial to the set-top box using this aerial lead, but for best results connect the TV to the box with a SCART cable.

You can also use a UHF lead to connect a set-top box to a television somewhere in the house. Your set-top box will require a RF (radio frequency) modulator. Note that "RF passthough" is another way of saying there is no modulator. You will be able to "tune" the second television into the picture showing on the set-top box.

Some boxes (all Sky boxes) have the ability to connect a remote control receiver to the second TV end of the interconnecting cable, so you can change channels.

The set-top boxes, whilst providing a reasonable quality picture to the second TV, will always provide only mono sound via a UHF lead.

The step-change in picture quality obtained by switching to RGB on a SCART is far greater than any obtained though spending any more on a gold-plated SCART cable.

Satellite or cable TV cable

These cables are usually very stiff, and have a very basic screw connector on the end. Usually they will provide an unbroken link to the satellite dish. At the dish end they plug into the device on the end of the arm, the LNB.

Don't try to disconnect these cables when the set-top box is on. Usually there is a small voltage that will cause dangerous sparks.

If the cable connects to a satellite dish, there is not much you can do with the cable. Each receiver in the set-top box needs it's own wire to the LNB. With a personal video recorder (such as Sky+), or a multi-room installations there are two cables to the four-output LNB on the dish. If you want more rooms, each will require it's own cable.

If the cable is providing cable TV, then it is possible to use inexpensive "Y connectors" to link the incoming signal to various set-top boxes, cable modems, or - via an adaptor - directly to the back of a TV.

Composite video cable

This is the most simple and basic video connection you can get. It carries:

  • a single picture from a set-top box

The picture will be in colour, and of comparable quality to a analogue broadcast station. However, there is no sound. For that reason this cable is often found joined to a stereo audio cable.

These signals are quite robust and can be carried for many metres. Often modern television sets have a single yellow photo input on their front input panel.

You also use an identical cable to carry digital stereo (SPDIF) sound.

Stereo audio cable

These cables carry the left and right channels of sound on two joined cables. They are usually required when a SCART cable is not being used, as the SCART cable already carries stereo sound.

If you are connecting your set-top box to an external stereo system, a separate stereo audio is used.

There is no real practicable limit to the length of these cables, but excessive length will degrade the quality of the signal.

S-video cable

The S-video standard is not well supported by most UK digital TV boxes, and very few have a S-video socket. If you need one for a particular analogue camcorder, use it, but avoid S-video with digital television. If you are using what appears to be a monochrome picture from a SCART lead, it will certainly by an incomplete S-Video signal and you should change to the RGB input.

VGA cable

This is the cable you will use to connect a computer to a old style monitor, and some modern LCD screen too. Most modern LCD TVs will have a VGA input too.

If you want to connect a set-top box to a LCD monitor, you can buy a conversion box from around 60. However this will not result in a better picture than using an existing SCART socket if there is one.

The only way to get higher than normal television resolution is to use a VGA in conjunction with a personal computer or modern games console.

DVI cable

If you want to get the very best out of a television or monitor use a digital video interconnect (DVI) cable.

This will be the only way for most televisions and monitors to receive high-definition pictures from a computer, and some set-top boxes.

If you can use either a VGA cable or a DVI cable, choose the DVI option.

HDMI cable

If you want to get the very best out of a television use a HDMI cable.

This will be the only way for most televisions to receive high-definition pictures from set-top boxes.

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Friday, 14 November 2014
10:06 PM

Hi mike
Well first things first the tv is a Samsung plasma 51 and the DVD player is a sumvision. I can't access the other Hdmi ports as the tv is fixed to the wall and there's no way I can move it, so I'm stuck with using the only accessible port on the side of the tv, hence my dilemma......and it still can't get it up and running. Should I try using the red yellow rgb instead?
I really wanted the hdmi option as its better isn't it?
Thanks for all your help up to now.

link to this comment
Minnie's 4 posts GB flag

11:05 PM

Minnie: OK - if the port on the side isn't working, and you cant get to the others, then you'll have to try another way. How old is the TV? A model number would help work out whats on the side, but if you have a red/white yellow set of connections, those are rca's, which would mean the TV was 3 years old or more.

Having those connections accessable would be a be a great help to you. The Sumvison is not a brand I'm familiar with, but a quick look at Amazon suggests that it has a scart and an hdmi. Yes, hdmi is better, but since its a dvd player, its not the end of the world not to use it. A set of rca connections (the red/white/yellow plugs) can basically be attached to a scart connection, using something like this: Scart Adaptor with 3 Phono Sockets - Black: Electronics - you just need the cables as well, but they are also really cheap. In fact a pound shop might do them.

Its not as good as hdmi, but if the port isn't working, you have to use what you can.

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MikeB's 2,579 posts GB flag
Saturday, 15 November 2014
11:44 PM

Mike B you're a star worked ...I now have DVD in bedroom :)
A million thanks from me and the amazed that a girl can do anything electrical boyfriend ;)

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Minnie's 4 posts GB flag
Tuesday, 18 November 2014
Tony Kilvert
8:25 AM

What leads do i need to connect my recordable free view to my sony bravia smart tv

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Tony Kilvert's 1 post GB flag

11:07 AM

Tony Kilvert: A simple wiring diagram should be in the manual of both devices. However, all you need to do is loop through the recorder so that the Tv also gets a signal, and attach an HDMI lead to connect the recordert to theTV

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MikeB's 2,579 posts GB flag
Thursday, 27 November 2014
Martin Everett
3:52 PM

How can I connect a free view box,DVD player to a TV with only one scarf connection please?

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Martin Everett's 1 post GB flag

5:21 PM

Martin Everett: Whats the make/model numbers of the Tv, Freeview box and dvd/

Or could you say what exactly the connections are on the back of each.

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MikeB's 2,579 posts GB flag

8:06 PM

Martin Everett:

One way is to obtain a SCART multi-adapter. Perhaps something like this: MULTI SCART ADAPTER: Electronics - other versions are available.

Else it depends on what sockets are available on the equipment, make and model numbers would help.

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MikeP's 3,056 posts GB flag
Saturday, 29 November 2014
David Hobbs
4:44 PM

I have a loop (I am deaf) connected to the TV by scart lead, how do I get the sounds to my TV from my BT Vision box and also my 3DBlue-Ray/DVD box and what Audio leads are required. Thanks

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David Hobbs's 13 posts GB flag

4:51 PM

David Hobbs: You say the loop is connected via scart - I'm not familar with hearing loops, but can I assume that its outputs via a scart?

Your BT vision box and bluray both should be attached via hdmi - and in effect the TV acts like a giant box, with sound coming out via the scart(?) . If not, the 3.5mm jack might do it.

If you could clarify how the signal comes into the loop, and also the make/model of tv, that might help.

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MikeB's 2,579 posts GB flag
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