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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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Thursday, 31 October 2013

6:03 PM

Ron Chase: Coupling a device with a scart socket output into another that uses a VGA input can in some cases be somewhat problematic, however such as the converter lead as seen on the link "might" solve the problem, but though its advisable to read (and note) the qualification made by the advertiser in the product description on the use of this product.

SCART TO VGA 2 M SCART LEAD TO 15 PIN HD - For more: Electronics

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jb38's 7,179 posts GB flag
Friday, 1 November 2013
Ian from notts

7:56 AM

Ron Chase- If the BTbox and the Moniter have the Video (yellow) Audio (red/white) jackplugs, they will provide a simpler connection.
There is no need to use an Amplifier between the BTbox and the Moniter, Tho you may need one between the Aerial and BTbox if the Freeview signal is weak

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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

6:26 PM

Ron Chase : Re: suggestion from Ian from notts regarding the possible use of composite video RCA type A/V sockets, although its to my belief that most models are not fitted with these type of connectors however they "are" fitted with a "S" video output socket, and so dependant on the model of BT vision box you are using you may have the choice of using an "S" video to VGA adaptor such as shown in the link, or possibly (monitor dependant) a simple A/V coupling.

AV RCA Composite S-video Input to VGA Output Monitor Converter Adapter CCTV DVD | eBay

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jb38's 7,179 posts GB flag
Tuesday, 29 April 2014
Patrick Dunphy
12:49 PM

i have a sky plus hd box and i want to connect the radio stations to my audio tuner which operates in another part of yhe house. The set top box has an optical cable outlet and a digital audio cable outlet. can i connect either of these outlets to my tuner and then listen to the sky radio broadcasts

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Patrick Dunphy's 1 post IE flag

1:59 PM

Patrick Dunphy: Sky boxes have a digital optical out, so if your amp has a digital opitcal in the back, it should work. However, thats likely to be a fairly long lead!

The other thing to think about is putting your amp/tuner online (via wifi or bluetooth), and streaming instead. Might be easier, since you can buy a bluetooth receiver for less than £20 7dayshop Bluetooth Audio Receiver - Links your car or home audio system / Hi-Fi to your Bluetooth device - 7DAYSHOP.COM

and then stream from a tablet, phone, etc. Of course you could use a streamer directly, perhaps Airport EXpress or the like.

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MikeB's 2,579 posts GB flag
Thursday, 15 May 2014
9:13 PM

I have a technosonic tv lcd 2603 with built in digibox and surround sound also in tv but unable to tune or connect them all together. Only have stereo with aux1' 2 so can't find how help.. Pls

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b.stallard's 1 post GB flag

11:10 PM

b.stallard: Since I've never heard of Technosonic (there is some chatter on the net about them being rebadged Thmsons), and can't find any manual, I'm having to guess at what on the back of the set! I'm also guessing that you've also got some kind of surround sound system, which might have a a pair of RCA phono's (red/white). If you have a list of the connections ('Connecting it all up' as a good page on them), and the make/model of surround sound system, that would be great.

OK - if you had a digital optical on both, then I'd use that. Since you've havn't mentioned them, I'm assuming they are not around, but still...

Most TV's from around 2006-1010 had twin RCA sound imputs, along with a yellow video input. They also had RCA outputs, as (hopefully) does the sound system. Thats what I'd use. It might just have a 3.5mm jack, at either end, but you can easly buy cables to convert to RCA.

Frankly, I'll need more info on the connections for both systems - can you list them both?

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MikeB's 2,579 posts GB flag
Thursday, 19 June 2014
4:56 PM

I have brought a Blaupunkt 23"tv, and I want to connect my Technika digital tv recorder to it, as it does not have a scart socket on the tv how do I connect to it?

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Elizabeth's 1 post GB flag

6:07 PM

Elizabeth: If the Technika recorder has hdmi, then use that, becuase thats the best connection anyway.

I'm not familiar with Blaupunkt (OK, looked at one in Sainsbury's..), but I'd be surprised if its didn't have one. It might be RGB (and if it is, then life gets complex), but have a look at the manual, and give us the model number.

To be honest, niether brand will have a huge amounts of connections on it, but hopefully we'll find something that matches.

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MikeB's 2,579 posts GB flag
Wednesday, 25 June 2014
Lorraine Copley
12:23 PM

I live in the Languedoc in France and have a satellite dish which is connected to an old Grundig Digibox DV3 and a Samsung LED TV UE40EH6030 and am trying to connect a Samsung DVDR120E player/recorder to them without much success as I cannot seem to get it to work at all - even just to Watch a DVD!!! The satellite dish is connected directly into the Grundig Digibox and I believe that the Scart lead should be connected to the TV from the DVD and then a link scart from the DVD to the Grundig Digibox - but the DVD does not work at all! can you please explain to me what connections I should bu using before it all goes in the bin. My Grandson is coming over from Canada on the day of the football world cup final and I have promised him that I will record the game for him!! so please help me.

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Lorraine Copley's 3 posts FR flag
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