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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, 21 June 2011
12:17 PM

can you help with connecting, toshiba plasma tv not hd, to humax digital recorder also panasonic dvd recorder i cannot record from the dvd recorder its very blurred, other than bbc 1 I have just got the latest aerial installed but i'm not sure of the connections.

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neville's 1 post GB flag
Tuesday, 28 June 2011
4:28 PM

Hi can you help me conect up my TV dystem i have a 46 in led hd samsung TV + samsung 5.1 blue ray cinema surround and a latest humax hard drive free view i am at present using 3 hand sets can you please help i want to use only 1 handset if poss

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mike's 1 post GB flag
4:57 PM

I have Sky+ (not multi-room). I have NO aerials in the house at all, and I want it to stay that way. I want to provide additional TV in the bedroom(s) and I am thinking of FreeSat. Is it posssible to connect a FreeSat box to my Sky Minidish to work alongside my Sky+ to provide existing Sky downstairs, and FreeSat upstairs.

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Vic's 4 posts EU flag
5:15 PM

Hello folks, need to pick your brains as having problems ?

Got BT Vision silver pack in october, just bought a samsung ue375220 smart tv very little idiot setup guide issued

I feel freeview and other isnt what I thought it would
Should only the hdmi cable be installed from bt vision box to tv or should I still leave the scart lead connected to the new tv too ?

the tv has a hd freeview box inside but it was saying on tv screen about something being too low for freeview ? I,ve checked my address and it says hd ready

I thank you for any assistance you could advise

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Gavin's 1 post GB flag
Wednesday, 29 June 2011
Frank Mulveen
5:30 PM

Hi. I just replaced my dvd player (Tevion) with a JVC one as the former packed in. Since doing this I can't select sky channels from my sky remote and when I use my tv remote to select an aerial signal (program 1) I get the AV1 channel. If I press program 1 again I get it. The only way I can get my sky remote to work is by disconnecting the dvd scart from the sky box. Can anyone shed some light on this? Many thanks.

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Frank Mulveen's 1 post IE flag
Thursday, 30 June 2011
lan from notts

7:56 AM

vic , yes. if you have sky+ you should be able to run 2 standard freesat boxes of the existing dish

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lan from notts's 253 posts GB flag
lan's: mapL's Freeview map terrainL's terrain plot wavesL's frequency data L's Freeview Detailed Coverage

8:37 AM

Frank Mulveen: This suggests that either you are keeping the DVD player permanently switched on, which cant really be done with some players using a daisy chain link scart connection such as you have, or that the scart cable you are using is faulty.

An easy way to check which it is being to disconnect the DVD player from the mains connection, (NOT scart as well) if all works as normal by doing that then the DVD player will require to be used on another scart socket on the TV, or if none available on TV you will just have to keep it disconnected when not required, on the other hand if unplugging the DVD from the mains makes no difference, then try changing the scart cable used between the Sky box and the DVD player.

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jb38's 7,179 posts GB flag

8:43 AM

Frank Mulveen: Forgot to add, that if it is the DVD thats causing the problem, for a test you could maybe try daisy chaining the Sky box through the DVD rather than keeping it disconnected. (sockets permitting on the DVD)

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jb38's 7,179 posts GB flag
10:10 PM

I wonder if you can assist me, I have a Samsung DVD-VR320 connected to my Sky box and tv. I have tried retuning using the system setup, but still find I am unable to change programme channels on the DVD Video recorder, which prevents me from recording sky box progammes onto DVD or Video. Do I need to change scart plugs or retune, but if so how, when I cannot locate channels on the machine.
Thank you for your assistance.

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Fmg's 1 post GB flag
Friday, 1 July 2011

7:46 AM

Fmg: I cant quite understand how you have the devices connected, as if you want to record something from your Sky box it should be done via a scart lead between both devices, the Samsungs input set to "ext input" or "AV2" etc depending on what it might be called on that particular device.

The only channels that your DVD/VCR combo can tune are analogue ones, and so won't come into the equation as far as what you are trying to achieve is concerned, unless that is you have the Sky boxes RF output fed into the Samsungs aerial input socket.

Maybe you could clarify regarding the channels you cant locate.

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jb38's 7,179 posts GB flag
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