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HDTV Connections Explained

So which audio and video connection goes where?

by Mark Hodgkinson Nov 6, 2014 - Updated: Jun 23, 2015


  • So you’ve read all our buyers guides, decided on your next TV and then comes the moment you finally get it home.
    Out of the box it comes and you’re ready to set it up but around the back and sides are a bewildering set of inputs and outputs. What equipment goes in where and what do all the stickers and labels mean?

    Let’s take a look…

    HDMI (High-Definition Multimedia Interface)

    This is your go-to input for your high definition sources and every HD video device manufactured now will sport an HDMI output. Amongst the many reasons it is favoured by the industry is that offers better protection against copying than analogue inputs.

    HDMI Version 1.4

    You don’t really need to worry too much about which revision of the HDMI standard your TV has but it’s worth pointing out that HDMI 1.4 brought with it the opportunity to carry HD 3D video signals. If your TV is 3D capable, it will be HDMI 1.4 equipped and any 3D sources available will carry corresponding outputs so, for example, just hook up your 3D Blu-ray Player to your 3D TV and away you go.

    Do I need a special HDMI V 1.4 cable?


    Well, HDMI cables don't have version numbers, they should be labelled as either high speed or standard. If you want 3D images and the likes of HDMI ARC (see below), you will need High Speed cables.

    What is HDMI ARC?

    The 1.4 revision also saw the introduction of the Audio Return Channel (ARC) functionality. You will usually find that a TV only has one ARC capable HDMI port so it’s important you get this one right. ARC is a very specific feature and, as the long name would suggest, it carries audio signals between the TV and connected AV receivers, soundbars or other audio equipment.

    The beauty of ARC is that it allows the audio signal of any sources connected to the TV to be taken out of it by a single cable. For example, in this instance HDMI 2 is our ARC capable port on the TV and it is connected to a soundbar. We can then have our Blu-ray player connected to HDMI 1, our games console through HDMI 3 and a HD set top box in to HDMI 4 and we can play the audio of each through the soundbar. Connecting thus will also allow you to use your TV’s remote to control the volume of the soundbar, thanks to HDMI CEC (see below).
    Choose HDMI Out out for soundbar connection
    Use the ARC input of your TV to connect at the other end

    Be warned that sometimes (quite often actually), the implementation of ARC varies between manufacturers and you may get issues with TVs and audio equipment ‘talking to each other’, which can necessitate pulling cables in and out and rebooting. It’s great when it does work, however, but be sure you have an HDMI cable certified as High Speed. It doesn’t have to be anything expensive.

    What is HDMI CEC?

    HDMI Consumer Electronics Control (CEC) is a feature designed to allow the user to command and control other CEC-enabled devices connected to the TV. So, for example, we could have a Blu-ray player connected to the TV but be able to use the transport and menu keys on the television’s remote control to operate it. Like ARC, we sometimes see some inter-manufacturer compatibility issues with CEC so you may need to use the dedicated controller if you can’t get things working properly and it’s often only available via one input – so check for CEC/EC labelling.

    What is HDMI 2.0?

    This latest revision of the HDMI spec is really mostly about 4K Ultra HD and we’d recommend when looking at 4K TVs that you check for 2.0 compatibility, at least via one of the HDMI ports. Whilst HDMI 1.4 is capable of carrying a resolution of 3840 x 2160 pixels, it can only do so at low frame rates, so it might not be future-proofed against advances in Ultra HD delivery technology. There are some other benefits but you’re not going to have to worry about them in the foreseeable future.

    Do I need a special HDMI V 2.0 cable?


    As per HDMI 1.4, you will need a HDMI cable labelled as High Speed.

    What is HDCP 2.2 and do I need to worry about it?

    The very latest version of High-bandwidth Digital Content Protection (HDCP) is 2.2 and you should get compatibility via any HDMI 2.0 labelled input; meaning when 4K Blu-ray players and other UHD video sources start to become available, this will be your go-to connection. For connected devices with older HDCP compliance (just about every HDMI device currently available), that are connected to HDMI 2.0 inputs, you might need to change a setting in the user menus concerning HDCP version, to ensure everything works as expected – check your owner’s manual for details.

    What is HDMI MHL and how do you use it?

    MHL stands for Mobile High-Definition Link and, as the name might suggest, it allows you to connect your phone or tablet to the TV to share its screen in larger proportions. It works using a special cable that connects the micro USB port of your mobile device and the MHL labelled HDMI input on your TV – again, you usually only get one, if any, on a TV. Older revisions of MHL allow for uncompressed video in 1080p and up to 8 channels of audio, while MHL 3.0 is all geared up for 4K with support for formats all the way up to a 3840 × 2160 resolution at 30Hz.
    Your phone might even be able to send the TV 4K material using HDMI MHL

    DVI

    If your equipment is even remotely up-to-date, you don’t really need to worry about this one but, in the infancy of High Definition TVs, sometimes a Digital Visual Interface connection was your only option. In most cases, the connection looks and acts like HDMI, only it doesn’t carry an audio signal, so you need to make separate provision for that using a corresponding audio input – it’s usually a 3.5mm stereo jack located somewhere near the DVI input and is labelled accordingly. About the only current use-case scenario we can conjure up for this, is when connecting your TV to a computer with an older graphics card and no HDMI support.

    Display Port Vs HDMI

    Televisions with a Display Port are very rare beats indeed. In fact, only the top-end 4K Panasonic’s carry a Display Port input, so if that’s something you think you might need, then they are your only choice. Display Port version 1.2, which the Panasonics have, is also capable of 4K video but at greater frame rates than HDMI 1.4. That said, outside of the computing world, there aren’t any Display Port sources so its need is only likely to be for professional use. Although some recent Apple computers have carried a mini Display Port output.

    Component video vs HDMI

    The component connection on the back of your TV might also be labelled Y-Pr-Pb, and you will usually find the three inputs are colour coded in red, blue and green to make connecting it to to your source that little bit easier. But this a connectivity option soon to be wiped from existence as, although it can carry HD signals, it doesn’t feature any HDCP (see above), so Blu-ray players - or other hi-def video sources, for that matter – no longer carry component outputs. Older AV receivers and games consoles are about the only likely current use. On newer TVs, you might well find your TVs component connection is shared with the composite one (see below), so it might require you to do some setting up in the user menus – again, see your manual.

    It’s important to note that Component doesn’t carry any audio signals, either, so you’ll need to ensure you have an audio cable coming in from your video source as well. Component cables often come with a couple of audio wires attached (usually white and red), so connect those to the corresponding inputs of your TV and outputs of your source. It’s also worth noting that there was a brief trend for TV manufacturers to provide ‘neater’ component, composite and Scart connections via adapters. These are often labelled AV1, AV2 and AV3, so you’ll need to make sure the relevant adapter goes with the relevant cable in the relevant slot.

    Why use Composite Video?

    Barring, perhaps, an older video camera, we can think of no good reason why you should be using a composite video connection. The quality is as low as you could possibly go so, if for example you’re still using your Nintendo Wii through the supplied cables, please seek out a proper RGB Scart (not the adapter in the box) or component lead to improve the picture quality. The composite input is usually colour coded in yellow/gold and needs separate audio leads for sound. Avoid wherever possible.
    The days are numbered for Analogue video connections

    Scart Input

    Whilst Scart can be a superior connection to composite, it certainly isn’t capable of carrying high definition video signals, so it’s another one on its way out. There will be many people out there still using it, however, with the likes of older set top boxes and DVD players that don’t have HD capability. The video signal in Scart can be carried in two ways; either in a composite signal (see above) or the more preferable method, like component, and split in to three signals giving better quality and usually termed RGB. You will need to ensure your video source is outputting an RGB signal in its user menus and that your Scart cable is fully wired – perfectly good cables can be picked up very cheaply nowadays. Unlike component and composite, Scart does carry an audio signal so you don’t need to worry about that.

    VGA connection

    There aren’t many new TVs that have a VGA (Video Graphics Array) input being produced, it’s all HDMI now. A VGA port might be useful if you want to hook up an older PC or perhaps an Xbox 360 to your TV but we really can’t think that many people actually currently still do this. Again, there is no audio signal taken over a VGA connection so separate provision for that will be needed.

    Does anybody use S-Video anymore?

    Unless you’re clinging on to your old laser disc player or have a penchant for nostalgic gaming, via really old consoles, you are never going to need to consider S-Video. In fact, the chances of your TV even having an S Video connection are beyond remote. The only video display device we’ve tested recently to have this archaic input was a budget Optoma projector, so at least you’ll be able to carry out your old-fashioned pursuits on a big screen.

    Audio Connections



    Toslink (S/PDIF)

    Whilst HDMI is perfectly capable of carrying its own audio signal, not all equipment you might directly hook up to the TV will have an HDMI port. In these instances, you can take digital stereo or multichannel sound out from the TV to the likes of a soundbar or an AV receiver using the optical connection. As we said above, HDMI ARC/CEC doesn’t always work perfectly (sometimes not at all) so it’s potentially a more stable option, although it doesn't give the benefits of auto powering on or being able to use the functions of the audio device, using the TVs remote control.

    Coax

    It’s less common for a television to have a coaxial output than it is a Toslink one but we do see them sometimes. For everything we said about Toslink, you can almost replicate for coax; it can carry stereo and multichannel signals and it usually just works, although it’s not usual to see coaxial inputs on a soundbar.

    Stereo RCA

    You might well find you have two sets of stereo audio connections around the back of your TV. These are almost always colour coded, in red and white, and have L/R (Left/Right) labelling. Where some confusion may arise is that the stereo connections could be inward or outward bound. Hopefully there will be a sticker saying Input/Output (or similar) next to them and the input jacks should have some indication as to which video input they correspond to. If all else fails – you guessed it – consult the manual.
    Almost all flat panel TVs have a digital optical out

    3.5mm Headphone Jack

    Sometimes all you get by way of labelling for this audio output is a graphic representation of a set of headphones. You don’t really need us to tell you what the primary purpose of this connection is but it can also be used to get audio to a stereo amp or powered speakers, if there’s nothing else you can use. We would advise it as the last possible solution, after Toslink, Coax or Stereo, however, as the quality of headphone amplification from a TV is often poor.

    Subwoofer out

    Just now and again, you’ll come across a dedicated subwoofer output coming out of the rear of a TV. To exploit it, you will need an active subwoofer of some sort, the appropriate interconnecting cable and you put that in to the mono input of the sub. By active we mean a subwoofer that has its own amplification and doesn't require the TV to power it - it should be obvious when looking at subwoofers which is which. Sony also makes a wireless subwoofer which can be connected to some of their TVs.

    Other Inputs



    USB

    Back when Smart TVs weren’t really that clever at all, a USB port on a television was quite a rare thing. Now, it’s not uncommon for them to have two or even three USB ports covering a variety of uses. The most usual way in which you’re likely to use one is by plugging in a thumb drive to view photos or videos on the big screen and just about every TV's USB port will allow for that.

    However, certain Smart TV features and accessories can only be used via designated USB ports. The most common examples are for video camera/microphone attachments and USB hard drives used for Personal Video Recorder functions. In almost all cases these specified functions will be labelled next to the relevant USB input but your owner’s manual will also have the details. A good rule of thumb would be, that when using PVR functions with a connected hard drive, you will need the input to be a minimum if USB 2.0, and USB 3.0 if dual tuners are involved.

    SD Card

    There aren’t too many televisions with SD Card slots but they are really useful for getting photos and videos from your camera to the TV, without the need to have your PC in the middle of the process. Of course, many people now share photos and video in lots of other ways but there’s something reassuringly fuss free and reliable about using a card.

    LAN

    A Local Area Connection is the absolute bare minimum for a Smart TV to have and most these days will have built-in WiFi capability, or at least a bundled USB dongle for wireless internet. Even some TVs without ‘connected’ features have a wired LAN port which can be used for software updates, so it’s worth connecting it up to your router, now and then, to see if your television is up to date.
    Beware, not all Satellite inputs are Freesat compatible

    Broadcast Connections

    Whilst every TV we can think of features a Freeview capable tuner – and most new ones are Freeview HD – satellite dish terminals are much thinner on the ground. There are only two manufacturers that support Freesat (HD) in the UK market – Panasonic & Samsung – so if you do see a television sporting a satellite connection made by anybody else, beware that you won’t get a proper EPG (Electronic Programme Guide), only Now & Next information. We’ve gone into more detail about the differences between Freesat and Freeview in a separate article.

    We think that’s all the bases covered but please do let us know in the comments section below, if your HD TV has a connectivity option we’ve missed.

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