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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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Tuesday, 5 February 2013
ian from notts

9:42 AM

doesnt the virgin box record programmes itself?
if noy you should be able to connect the virgin box to the sagem using a scart lead and record onto the sagem thro the setting av/ext 1 or 2

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ian from notts's 253 posts GB flag
ian's: mapI's Freeview map terrainI's terrain plot wavesI's frequency data I's Freeview Detailed Coverage
Sunday, 10 February 2013
12:15 PM

hi i have a zt pad running on addroid and want to connect it to my tv useing hdmi but it won,t connect

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jerry's 1 post GB flag
1:13 PM

I have a new LG Freeview DVD player/recorder and trying to connect to a Panasonic TV.
I have connected them as per the instructions with a SCART lead via AV1 on the TV. My problem is that when I turn off the DVD to go back to TV, the TV screen thins and you cannot change the channel.
It appears that the only way to get the channels back on the TV is to switch off both DVD and TV and re set from the start. Also I have to switch off the TV to start up the DVD.

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Pam's 1 post GB flag

5:44 PM

Pam: Are you feeding the aerial to the TV through the DVD recorders aerial in / out socket? also try connecting the DVD recorder into the TV's AV2 input and then when you want to play back anything previously recorded select AV2 input on the TV's input select button.

What model of LG recorder you are using?

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jb38's 7,179 posts GB flag

7:35 PM

Pam: Just to add to that said, if you are viewing something on the TV and then switch on the DVD recorder does the TV automatically switch over to the recorder? and yet when the latter is switched off again it doesnt revert back to the TV? if this is whats happening then the next time it does it pull out one end of the scart connection between both devices, because if this enables the TV to return to normal viewing then that particular DVD recorder is not compatible with the normal method used to couple devices of that sort together.

By the way if your TV does not have an AV2 input then the only way I can see out of this problem is to snip pin 8 on the rear (internal) of the scart plug as thats the switching pin, then when you want to use the recorder select AV1 on the TV's input select.

Maybe you could also mention the model of the Panasonic in question as well as the LG recorder.

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jb38's 7,179 posts GB flag
Monday, 25 February 2013
Lynn Leland
7:10 PM

Hi Hope you can help me please. My inlaws had terrible screen break up and freezing on their tv so they had a new aerial fitted. Although better it still never completely cured the fault so they purchased a goodmans set top box with a single scart connection. their tv also has only one scart connection but they also have a dvd player to connect up as well. I bought a 2m Scart Splitter Cable - 1 to 2 High Quality / Fully Wired / Shielded / 21-pin / Audio / Video / Male to 2 x Male and connected all up but now the sound is very very low on the tv even though the sound is maxed. Wonder if you have an ideas why this is such. Many thanks Lynn

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Lynn Leland's 4 posts GB flag
Dave Lindsay

8:38 PM

Lynn Leland: Probably because there is a volume control on the set-top box which is independent of the volume on the TV.

Evidently, the volume on the TV is high and the volume on the box is low.

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Dave Lindsay's 5,724 posts GB flag
Tuesday, 26 February 2013
Lynn Leland
9:00 AM

Thanks Dave for your response but the volume on both the set top box and tv is maxed but still too low. the sound was fine when only the tv was connected to the set top box via a single scart lead. the problem has only arisen since placing the new splitter cable so able to connect the two devices.

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Lynn Leland's 4 posts GB flag
Dave Lindsay

10:15 AM

Lynn Leland: I'm not entirely sure that you can use a "splitter" to combine two feeds into one.

Judging by its name, I would say that its purpose is to split one output into two outputs. What you're trying to do is combine two outputs into one output.

You may be able to daisy-chain the DVD and Goodmans if at least one of them has two scart sockets.

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Dave Lindsay's 5,724 posts GB flag
Lynn Leland
12:33 PM

Dave Lindsay : Ah I see. Both the set top box and dvd player only have one scart socket so how about if I get a scart switch box with 2 sockets. Do you think that would do it?

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Lynn Leland's 4 posts GB flag
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