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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, 25 August 2011
Pete Rostron
2:52 PM

Briantist No mate its not the laptop I want to connect, that works fine, I was just using the laptop explanation to let everyone know its not something wrong with the TV (SVGA input). It was my desktop pc monitor that got cracked. In effect I want to use my TV as a giant monitor. would your idea work with a desktop pc do you think? I can plug it in to a friends monitor press windows+P change to projector, disconnect from the monitor and plug into the TV...not at home atm but could try this later, do you think it would work

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Pete Rostron's 2 posts GB flag
Saturday, 27 August 2011
j crofton
7:01 PM

can anyone give advice on how to connect a dvd player into tv we also have virgin and a video recorder

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j crofton's 1 post GB flag
Monday, 29 August 2011
5:40 PM

Hi , I have a Freeview tv in the living room which i have connected to the outside aeriel which is a great picture. My problem is , when I put a connector into the aeriel socket to run an aeriel lead to a second Freeview Tv in the bedroom it wont pick up any channels. What sort of cable do I need , can anyone enlighten me on this please ?


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Alan's 1 post GB flag
11:30 PM


It would be great if someone could give me some advice please. I've just set up my Mum's new Panasonic DVD Recorder, to her old (pre-LCD) TV via a scart lead. I found that once set up, you have to press the AV button on the remote every time you want to change channel (it reverts back to the analogue channel) - is there a way of getting the TV to switch to AV on it's own? I've used a decent scart lead; I believe the current TV setting is RGB. I now probably sound like a total fool! Thanks in advance for any help out there...

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Miriam's 1 post GB flag
Tuesday, 30 August 2011
kB Aerials Sheffield

8:42 AM

there are usually a couple of scart sockets on the back of the dvd recorder - usually scart 1 sends a controll signal through to the tv to tell it to turn to it
if you have connected via scart 1 and it doesn't change the tv to av1 then check to see if scart control is an option in the menu and switch it on

after setting up hundreds of tv's and vcr/dvd systems over the years one thing ive found is each combination works slightly differently - annoyingly there seems to be no rhyme or reason to it and its a case of sitting there figuring out how the setup your working on works before instructing the customer on the use!

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kB Aerials Sheffield's 274 posts GB flag
7:45 PM

We have a Samsung LED TV with no scart sockets but 4 hdmi ports. How and what do i need to connect my Sky plus box to the TV???

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Kim's 1 post GB flag

9:14 PM

Kim- Are sure the set does not have a Scart socket? As it is an LED backlit TV, it may have a socket marked 'RGB'. If it has, you may need a lead that fits this socket and the other end being a Scart socket. If this is applicable to your set, you can then fit your Sky-box via this method.

Hope this helps

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LutonFan's 382 posts GB flag
kB Aerials Sheffield

11:20 PM

Kim - these tv's usually come with a scart adaptor to a small what looks like Headphone socket at the back of the set - unfortunately I have known customers throw these connectors out with the packaging - check the instruction manual - the bag of bits its in there might be one there (should be one supplied) with all the bits


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kB Aerials Sheffield's 274 posts GB flag
Wednesday, 31 August 2011
Frank Thomson
11:31 AM

Hi - hope someone can help here?

Gone totally digital now from Waltham Transmitter. However, same problem is occurring. ITV1, Channels 4 and 5 - picture fine but lots of problems with BBC1, 2 etc. The picture is quite clear but continually stalls, i.e. stops and starts and the sound does the same. There is also a clicking sound coming from the tv.

We have an analogue Panasonic TV with a Humax PVR Freeview box. We have also got a DVD digital player. We got the Technician from John Lewis to come and have a look at the Freeview box, but he said this was OK and that it was our SCART extension box which was at fault. We have since gone to Maplins and got another one - but there hasn't been any change in the problem with BBC. We have tried every permutation with the boxes but to no avail. Is the transmitter to blame for the poor quality of the BBC channels? We are tearing our hair out with all these problems. We can record and we seem to have all the new channels that we what is the problem, anybody out there?

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Frank Thomson's 5 posts GB flag
Thursday, 1 September 2011

8:05 AM

Frank Thomson: Can you please have a look at the Single frequency interference | - independent free digital TV advice page?

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Briantist's 38,915 posts GB flag
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