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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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Wednesday, 16 November 2011
11:59 AM

How do i connect a Humax hd box to my sony tv and sony dvd recorder, all have 1 HDMI socket and 2 scart sockets.

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Alan's 1 post GB flag
Saturday, 26 November 2011
4:36 PM

alan - - the human box has a HDMI output the tv has a HDMI input -connect the 2 together thats one sorted

I assume the DVD recorder has a scary socket
connect the scart from the recorder to the TV

also if you wish to record from the Humax to the DVD recorder connect a scart lead from the humax scart socket to the dvd's spare scart socket (blooming auto correct just corrected Humax to Human and a SCART lead was corrected to SCARY - New mac osx Lion)

link to this comment's 2 posts GB flag
Tuesday, 6 December 2011
12:05 AM

I have a samsungPS42P25B monitor with only a female dvi connection. How is the best way to connect this to my virgin box so that both audio and visual work

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bob's 1 post GB flag
Wednesday, 7 December 2011
Bryan Wensley
11:55 AM

How do I connect a Freeview HD box to a Hard Drive recorder & TV to enable me to watch & record HD programs ?

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Bryan Wensley's 2 posts GB flag
Dave Lindsay

12:45 PM

Bryan Wensley: Using HDMI leads.

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Dave Lindsay's 5,724 posts GB flag
Bryan Wensley
3:05 PM


I presume this will still record in HD even if my recorder does not have an HD tuner ?

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Bryan Wensley's 2 posts GB flag
Bryan's: mapB's Freeview map terrainB's terrain plot wavesB's frequency data B's Freeview Detailed Coverage
Neil Bell

8:42 PM

Bryan Wensley I have a Fortec Star Passion Plus HD free to air satellite receiver which has one HDMI output and I have been using this with a Sony RDR HXD 870 DVD/Hard Drive Recorder but this has no HDMI input so I can only use SCART leads (or phono inputs on the front panel).

I think that this absence of HDMI inputs is fairly typical on recording equipment although I'd like to hear from someone in the know if I've got this wrong. E.g. I have more recently bought a Panasonic DMR-BWT700 Blu-ray Recorder and was disappointed to find that it too has no HDMI inputs so can only record in true HD by using the internal freeview HD tuner.

However I have found that the quality is much better when I record HD programmes on the DVD recorder from satellite than when recording SD programmes despite using a SCART lead. On the odd occassion that I have watched an HD programme on TV connected by HDMI lead and recorded it at the same time on the DVD recorder I haven't noticed any degredation in quality when I've played it back later (although this may be the subjective judgement of my 64 year old eyes!) I've yet to try recording an HD programme from satellite on the Blu Ray recorder but almost certainly will when I'm home over Christmas.

So in brief you should be able to record HD programmes on a hard drive recorder but you will probably have to use a SCART lead. If the hard drive recorder has an HDMI output you should of course connect it to your TV using an HDMI lead.

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Neil Bell's 106 posts CZ flag
Thursday, 8 December 2011
Paul Mitchell
3:33 PM

is it possible to connect
a digital recorder to
a flat screen tv (only has one scart)
a bluray player
and dvd/video combi? (2 scarts)

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Paul Mitchell's 1 post GB flag
Friday, 9 December 2011
11:32 AM

help i have a tv with freeview built in and sky but my freeview doesnt work how do i connect all the cables

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pat's 1 post GB flag
Saturday, 10 December 2011
John Maloney
11:24 AM

My dvd player recently started playing up.
For some reason it will not load, and I cannot get the tv to recognide the hdmi connection- no signal message. The dvd works fine with a scart conection,
which seems to be the default when connected with hdmi and scart.
Sky HD box works fine.(this is connected to port 3 on my Samsung- hdmi/dvi-is this correct?)
I have tried everything without success, and
I don't want to buy a new dvd
(not Samsung just to overcome connection problems.
Any advice would be welcome.

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John Maloney's 3 posts GB flag
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