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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.

Help with Television sets?
Why are all TVs on sale not digital?1
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I Have a Pocket Tv For taking out so I can keep up with news and sport. Will thi4
The pictures from my digital box are all green!5
In this section
Loft aerials1
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How to receive Freeview on your PC3
Indoor aerials4
Whole house digital TV5
Now and Next6

Friday, 23 September 2011

4:51 PM

darrell: Its extremely unusual (although not impossible!)for an aerial amplifier of the type you mention to go faulty, are you positive that the problem is not connected with your TV?

If the green light is on then that indicates that the DC side of the unit is working, that is if its the type that indicates red if a short occurs anywhere in the co-ax line.

I would normally say that you should try connecting the downlead straight into the TV, and likewise by-passing the amp in the loft, but I suspect that the downlead (and amp) might be terminated in "F" type plugs, this making this a bit difficult for you without "F" to co-ax adaptors.

What you could do though is to ask someone to observe the green light whilst you go into the loft and quickly temporarily short the co-ax plug on the downlead, if the green light turns red then its the amplifier at fault. By the way you will not harm the power unit by doing that, although a test meter would obviously have been preferential to check this.

(Its not an amplified log you are referring to is it?)

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jb38's 7,179 posts GB flag
Tuesday, 27 September 2011
9:51 PM

darrell: hi jb,its a small white box,ive bypassed the amp straight into tv but still the same but only picking up 19 digital channels but no bbc ,itv .do thing its the tv,s? thxs jb

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darrell's 2 posts GB flag
darrell's: mapD's Freeview map terrainD's terrain plot wavesD's frequency data D's Freeview Detailed Coverage
Sunday, 2 October 2011
5:52 PM

Hi, i've got a sky HD box in my living room with a HD ready tv. want to connect this to my small portable digital tv in the kitchen. do i have to pay sky money for this or can i use a cable to connect? and if so what type of cable / connection would i use? I'm already paying a small fortune to sky as it is and would really grudge giving them any more money. thanking you in advance for any help, would really appreciate. Just came across your site during a web search and impressed with the advice you've given.

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Carla's 1 post GB flag
Tuesday, 4 October 2011
Jim F

10:34 AM

Carla: No additional payment required. Use a coax cable to connect from the Sky box rear panel RF2 socket to the kitchen portable.
You'll need to set the kitchen portable to "analogue" (if you're in a pre-switchover area, use a button number above everything else, such as 6) and you'll have to tune the kitchen TV to the same RF channel as the Sky box (default is UHF 68).
You'll only get the same Sky channel as the living room (only one Sky box).
If you're feeling adventurous, you could add a remote eye to be able to change the Sky channel from the kitchen (you'll need to access the installer menu on the Sky box and enable the 9V power for the RF2 socket though).

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Jim F's 141 posts GB flag
Friday, 7 October 2011
7:54 AM

Hi,could you explain to me I have conected my dvd to my freesat but when I play a dvd the picture comes through on top of another station

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Angie's 1 post GB flag

9:28 AM

Angie: You haven't mentioned Freesat what, TV or Box? however the problem would suggest that the scart lead you are using is either faulty or not fully seated into the socket properly, check either end.

If though its a box, try reversing the scart plug socket positions used on the box.

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jb38's 7,179 posts GB flag
Saturday, 8 October 2011
4:39 PM

Hi, just bought a DVD recorder and expensive HDMI cable.
Unhooked the old DVD rec. with scart leads and replaced with new one a new leads.
I have Virgin V+ topbox.
I can get everything working except I cant get the new DVD rec. to tune into V+ box. Have DVD autotune on TV screen but it finds no channels. I have tried all permutations ( I think) of connecting these three together to no avail. The original signal is on a split to top box and DVD. Heeeeeelp! Linda

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Linda's 1 post GB flag
KB Aerials Sheffield

6:02 PM

Linda use a scart lead via your new DVD recorder and the virgin media box -- Off course if both the virgin box and your recorder have a scart socket --- then select the appropriate input on your DVD recorder

AS for buying an expensive HDMI cable without being rude you have probably been ripped off as there is ZERO difference in picture quality between an expensive HDMI cable and a cheap £5 one

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KB Aerials Sheffield's 274 posts GB flag
Sunday, 9 October 2011
5:28 PM


My brother is autistic and likes to play his video tapes however since the switchover he has found this increasingly difficult. In their lounge my mother has an old tv, settop box and a video recorder (she is a pensioner 76 and this was all set up for her for a fee. The problem is with the digital tv she has in the kitchen, the old vcr plays tapes in both the lounge and kitchen but when it broke and we found another vcr for my brother it works in the lounge fine but will not work in the kitchen on the digital tv? when we tune in the digital tv we find the video channel but it will not save it and as soon as we have the digital channels on we cannot find the video channel? any ideas what we are doing wrong? Kind regards

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PJ's 2 posts GB flag

7:35 PM

PJ: There should be no difference whatsoever with the new VCR as far as it operating with the kitchen TV is concerned, provided that is nothing has actually been changed in the kitchen.

The only thing I wondered about is whether the new VCR is coupled to the lounge TV via a scart lead? as if that's the case then the VCR's RF output channel will most likely be set on a different channel to the one previously used by the kitchen TV, so either the kitchen TV requires re-tuning whilst its set on ANALOGUE to pick the VCR's RF output up, or alternatively the VCR's RF output requires altering to match the channel used on the kitchen TV. (provided you haven't scrubbed it by re-tuning)

You have to be careful though, as you might adjust the VCR's RF output to a channel that clashes with a Freeview one, that's why it would have been better to tune the new VCR to suit the kitchen set, as I take it Freeview was OK with the previous set up.

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jb38's 7,179 posts GB flag
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