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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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Sunday, 3 July 2011
s. wilkie
9:17 PM

now that Ihave a set top box I find that I cannot get AV3 channel in order to download images from my camcorder to the tv screen via the vcr. the link between vcr and tv seems to be ok because I can see the video no matter which channel is on the tv when I press play.How can I download from my camcorder?

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s. wilkie's 1 post GB flag
Monday, 4 July 2011

7:45 AM

s. wilkie: If the link between the VCR and the TV is OK then there is no reason that you cant see your camcorder, as all you do ON YOUR VCR is to select "ext input" or whatever AV number corresponds to the input sockets you are using on it to feed the camcorder into.

This being said assuming that you are using the camcorders A/V output socket with a lead that has either two, or three coloured phono (RCA) plugs on one end, these being used into the VCR, that is unless you are using one of the later types of VCR combo's that has a DVi input for camcorder purposes.

By the way yellow always being the video connection on any of these non-digital leads.

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jb38's 7,179 posts GB flag
Tuesday, 5 July 2011
Sandra Shadrach
8:46 PM

I need some help from someone who is familiar with OLD technology!

I have a Sky Digibox (we live in France) and the old Sky card, and used to be able to get the free to air stuff on Sky. Left this little lot with some tenants, who used their own Sky Box and left without reconnecting our one.

Now I try to do this cannot get it working. The digibox works, the local French TV shop checked it for me (they had to supply a power lead as the tenants made off with that as well...). They also supplied a Scart output cable to connect to my old Sony Trinitron TV via 3 colour connectors, yellow, white and red. These go into my AV input bits on the TV.

Only problem is, no signal.

What TV system should i use, and how do I tune the old Sony to find this signal on AV1,2 or 3?

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Sandra Shadrach's 1 post FR flag
Monday, 11 July 2011
Robin Soule
10:04 AM

I have bought a Samsung Seruies 5 T V but wish to use my old SKY Grundig Box with it - the new TV does not have a SCART connection plug on the back - I have received a Scart Connection Cable with the |TV but the other end of the lead is not and HDMI fitting type so will not fit in the side of the new TV - am I missing something simple that I can use to connect up?

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Robin Soule's 1 post FR flag

1:40 PM

Robin Soule: Terrible as it is to say when dealing with a high tech TV, but if your TV doesn't have a scart socket then the only way you can use your old Grundig Sky box with it is via the RF output facility on the Sky box, this being fed into your new TV's aerial socket, analogue being selected on the TV before scanning to pick up the Sky box.

The designers of these later models of Samsung TV's looking at scart connections as though they are something from the dark ages!

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jb38's 7,179 posts GB flag
Tuesday, 12 July 2011
Sid Barnett
9:15 AM

Hi Briantest,

Can you tell me how to connect my TV to Sony DVD recorder to Sky box in order to recoprd from Sky. I am a Sky customer.

My Tv is a JVC 28WFR1EK with three scarts marked EXT 1,2 ,and 3.

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Sid Barnett's 3 posts GB flag
Wednesday, 13 July 2011
brian farren
3:31 PM

i need to connect my top up tv box to a television with an external freeview box can u tell me how i do this

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brian farren's 1 post GB flag

5:09 PM

brian farren: It would be somewhat easier to give an exact answer to your question if you had mentioned the brand / model of Top Up TV box that you have.

Also, whether or not the TV being used has more than one scart socket?

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jb38's 7,179 posts GB flag

6:09 PM

Sid Barnett: As your TV has three scart sockets its best to use this method.

Connect the Sky boxes scart socket marked "TV" to the TV's Ext1 - then connect the Sky boxes other scart marked "VCR" to likewise on the DVD recorder - finally connect the scart socket marked "TV" on the DVD recorder to the TV's Ext2.

Operation - If you want to record from Sky select Ext2 on the TV, this switching it over to the Sony DVD recorder which is permanently on Sky channel "if" the DVD's input selector is set to "VCR", (or whatever its called on that set) you can then select whatever type of recording mode you wish to use for your recording.

Once you have set this up, or started recording as the case may be, you can switch the TV back to normal viewing channels again, likewise if you want to view what you have recorded later on just select Ext2 again.

There is a simpler "daisy chain" method that could have been used, but this is not always advisable as "some" DVD recorders lock the TV on their input socket when they are powered up, even in standby, so its best to keep DVD equipments on a separate input on the TV.

Regarding aerial connections, you haven't mentioned the model of Sony DVD recorder you are using, but its always best to use a separate aerial feed to it as the loop through "might" falter when the device is in standby, this resulting in the "normal" TV channels going down, so the addition of a simple powered two way splitter would suffice, one output for the TV and the other for the DVD recorder.

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jb38's 7,179 posts GB flag

9:32 PM

Sid Barnett: Meant also to add, that with everything set up this way the Sky box will (or should!) always over ride anything being viewed on the TV at the time "if" the Sky button on the remote is pressed, as a TV's Ext1 (or AV1) scart input socket is usually the only one capable of auto switching when the device connected into it is switched on.

If on an odd occasion it doesn't, flicking Sky into standby then back on again usually resolves the issue.

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jb38's 7,179 posts GB flag
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