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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, 16 October 2014
M Bevan
12:11 PM

Just to let you know.
Advised to enter post code from nearby to transmitter, as my post code in TT TV Box. Switch off at mains and when turning back on it found 11 more channels including BBC News HD & Motors TV. Although Motors TV is not watchable this morning due to poor reception, BBC News HD is fine.

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M Bevan's 3 posts GB flag
M's: mapM's Freeview map terrainM's terrain plot wavesM's frequency data M's Freeview Detailed Coverage
Saturday, 1 November 2014
2:43 PM

Whats the best way to connect smart TV to Panasonic home theatre and Humax freeview set top box recorder?

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phil's 1 post GB flag

4:02 PM

phil: The model numbers of all three devices would have to be known in order to find out the input / output connectors provided on each of them, because as far as these facilities are concerned no common standard exists, every manufacturer having their own ideas on the subject.

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jb38's 7,179 posts GB flag

7:33 PM

phil: OK - your TV has probably 3 HDMI's and a single scart, plus probable RGB's on the back (model?). The Humax will have a scart, RCA's and probably an HDMI (9200 series onwards - again a model?). The home cinema is more of an unknown (model would be a huge help), but if its from the past 5 years should have HDMI, and possible scart/RCA. There should also be a digital optical on the back of the TV, Humax and Home Cinema.

Start with the best connection first. HDMI 1 on the back of the TV to the Humax. Its the thing your using most. Next, if you've got an HDMI in the back of the Home Cinema, use that as well, in HDMI 2. You'll benefit from Viera link, so you can control the volume with the main remote, upscaling, and if the Home Cinema & TV have 3D/ARC on HDMI, then you just need to connect a 3D capable HDMI to both, and then you'll get great sound as well.

If its not ARC, then use an HDMI (for all the above stuff), but use a digital optical from the home cinema to the TV. It shouldn't need it, but it seems to work better. The sound from the Humax will come into the TV, and then out to the Home Cinema, and hopefully avoid any sync problems.

Model numbers would help narrow down the possibilities.

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MikeB's 2,579 posts GB flag
Saturday, 8 November 2014
8:49 AM

I am reconfiguring and decorating our lounge with the TV on a different wall now from our sky box ( soon to be Virgin) and have the opportunity to run cables under the floor and chase them in, only which cables for now and the future? Currently we have HDMI from sky box to TV and optical from TV to a sound bar attached above but expect we will get a home cinema at some point with box being located with sky / virgin box. Should I run HMID cable alone to the TV socket as currently but what about future sound? Can that come from sky / Virgin box to home cinema and then speakers ? Help! thanks

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Guy's 1 post GB flag

1:08 PM

Guy: its good your thinking about the future, and nobody wants to plaster more than once!

You dont say how old your TV is, but some things are now standard, such as wifi. However, cables just work, and its easier to put something in now, so you always have a fallback.

The first thing is power. One for the TV (and think where the socket will be on both your current, and any future TV - certain brands have power and inputs on one side, some the other), and one for a possible soundbar (my gut feeling is thats what you'll end up with, especially since the TV is wall mounted).

Even if you have Virgin/Sky, I'd still put in an aerial lead. A - you might as well, since you've paid for it and it gives you more choice, B) - you might not always have Virgin, etc, Your TV might also have a Freesat or generic sat. tuner (or any new TV might have one or two). You might as well have a coax to serve that.

4 HDMI's are great (pretty much the max your'll get on any modern TV), and probably best to make them 1.4, so they will handle 3D, ARC, etc. You'll need them for any extra boxes, streamers, soundbars or blu-rays.

Have a look here for some discussion of soundbars, etc Having problems with TV background music? - some just have digital optical, many use HDMI, and some soundshare (depending on your TV). Even Sonos and Bose sound systems use digital optical (reflecting their background as audio manufacturers, rather than TV manufacturers), so it might be worth bunging that in as well, especially if your already using that with your current system.

Since all TV's are now smart and have wifi, you could do without ethernet, but its a more reliable connection, etc, so pop in one of those as well.

Thats fine for the cables, but I'd advise you to go and ask some questions about what you want for audio in the long term. Although they still make the classic 'home cinema' system (2.1, 5.1 or 7.1 plus a bluray in one big box with lots of speakers), I havn't seen one in a couple of years. So if you do buy one, you probably wont have heard it first. Blu Ray players are now so cheap that people are buying bits, and fitting them together as they want.

Soundbars are the main thing now, and they are increasingly becoming part of larger systems, like Sonos, Pure, etc. Buy a speaker, put it where you like. The Sonos Playbar connects via digital optical, but connects to the rest of the system via wifi. Add extra speakers at the back for surround sound, and a sub, etc. Not cheap, but very flexible and popular. Lots of other brands are doing something similar. Samsung are doing exactly the same thing, but are coming from the other direction, starting with the soundbar, but able to add extra speakers.

I'd want the sound to come via the TV (HDMI, bluetooth or digital optical). You can use the Virgin box, etc, buy you might cause sync problems.

BTW - if the wall mount moves (so you can swivel the TV, etc), think of the extra length of cable your going to need - remember its going to be a good six inces of extra cable to reach.

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MikeB's 2,579 posts GB flag
Thursday, 13 November 2014
1:40 PM

I want to connect a DVD player to my tv via hdmi cable. Do I need to use an aerial as currently I get freeview through my talk talk box directly to the tv.
The back of my DVD player doesn't seem to have a socket for an aerial, it's all a bit confusing for me as you can tell I'm a novice .......and blonde!

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Minnie's 4 posts GB flag

2:10 PM

Minnie: The DVD player is just that...a player. All you need is a HDMI lead, and follow the DVD's/ TV manual for connecting it up.

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MikeB's 2,579 posts GB flag
10:04 PM

Thanks Mike B. :) I did just that but when I source the DVD on the tv it comes up with HDMI 3 not supported.
I've tried the cable and the DVD player with another tv and it's fine. I dont have any problem with HDMI 2 which is my talk talk freeview box/recorder. I must be doing something wrong but I just don't know what.
Help please or my boyfriend is going to think I'm just incapable of doing anything on my own. He is macho man and pretty much thinks women should just stay home and cook!


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Minnie's 4 posts GB flag

11:18 PM

Minnie: A model/make of the TV would be useful, but basically, you should just be able to plug in the hdmi cable to connect the tv to the player, switch on the player, and off you go. Its sounds like you've got 3 HDMI ports, so I suggest the following:

You know HDMI 3 works, because your talk talk box is connected to it. Try swaping over the cables, so the talk talk goes into hdmi 2. If nothing works, you know its the hdmi port on the TV at fault (it happens, as someone the other day found out). If it works, then the port is fine.

Plug the DVD player into the port where the talk talk box was - you the port is fine, so if it doesn't work, then its the cable. Since you've tested them already in another TV, its probably the port.

Since you have 3 ports, wouldn't it be easier to use HDMI 1 for the talk talk, since you proably use that the most? Whatever is easiest to you, but even if one HDMI port is duff, you should be able to use the other two.

Let us know how you get on, and we'll help if we can. Your boyfriend will never know!

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MikeB's 2,579 posts GB flag
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