what does directional mean?

Discussion in 'Blu-ray & DVD Players & Recorders' started by 7 of 9, Feb 12, 2003.

  1. 7 of 9

    7 of 9
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    on scart leads what does directional mean?
     
  2. simonb68

    simonb68
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    Cables that are directional are designed to work best when used in the specified direction. Arrow should run from the source component.
     
  3. Underscore

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    It means that you've just paid twice as much for the interconnect with no noticable improvement in quality! :D I've never understood the logic of directional cables. I mean, the signals are AC, with a zero DC component, so for every time the current is flowing in one direction, it spends an equal amount of time flowing in the other. So, how exactly does a directional cable improve anything?

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  4. NicolasB

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    The way a SCART plug is laid out different pins are used for input and output of audio. So to connect two SCART sockets together you have to run a wire from the audio output pins of one socket to the audio inputs of the other. A fully wired SCART cable will wire the input pins of each of the two plugs to the output pins of the other. A directional cable has less internal wiring - the output pins of one of the plugs is wired to the input pins of the other, but not the other way round.

    So, suppose you're running a SCART cable from a VCR to a TV, and the TV produces an audio output on its output pins, if the cable is directional then it will feed audio from the VCR to the TV, but not the other way around. That potentially cuts down on interference inside the cable and requires slightly less internal wiring.

    This is usually more of an issue when the cable is a SCART to S-Video adapter: on one end is a SCART plug, on the other is a 4-pin S-Video plug and a pair of phono plugs for the audio. If you want to use this cable to pass a signal from the SCART end to the S-Video end then the phono plugs need to be connected to the SCART plug's audio output pins, but if the signal originates from the S-Video end then the phonos must be connected to the input pins. Some cables like this are switchable, others are hard-wired to work in only one direction.
     
  5. James45

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    directional cables do not only send signals in one direction, surely that would brake some pretty major laws of physics, how could a signal only travel in one direction along a cable.
    The idea is to use the cable in the same direction all the time ie with the indicator arrow pointing from DVD to TV all the time, not using it like that for a while then taking it off and fit it in the opposite direction.
    The theory is that the flow path of electrons along the cable 'burn in' and make the cable better when used in that direction. It's not just scarts that are classed a directional either.
    To my mind directional cables are a nonsense, I had a qed rgb only 'directional' squart for a couple of weeks recently and it was a lot noisier than the cheaper good quality scart that eventually replaced it.
     
  6. Underscore

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    Which is a load of bollards since the electrons move equally in both directions for an AC signal. While on the subject, someone posted a great quote about cables on the DVDForums the other day. Had me in stitches...

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  7. James45

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    maybe I should of said the 'manufacturers jargon' rather than theory!:D
     
  8. LV426

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    There IS such a thing as a directional SCART!!!!!

    The SCART specification is bi-directional. By which I mean:

    With a single multi-pin plug, it can

    a) take an array of output signals from device A and supply them to the inputs of device B

    b) take an array of output signals from device B and supply them to the inputs of device A

    at the same time. For example, the composite video signal OUTPUT pin on the plug connected to device A is wired to the composite video INPUT pin on the the plug connected to device B. These are different pins.

    And vice versa.

    A directional SCART cable has an incomplete set of wiring inside. At one end, the OUTPUT pins are wired up, and at the other end, each core is connected to the corresponding INPUT pin. But NOT vice versa.

    Why?: Prevents crosstalk between input and output from occurring in the cable.
     
  9. NicolasB

    NicolasB
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    Didn't I just say that? :mad:;)
     
  10. James45

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    yes I suppose in the sense of having only certain pins wired in a multi-pin link like a scart, that would be directional. I was talking about single cables... which is off topic i guess... so I'll shut up!:D I'd still prefer a fully wired scart for the flexibility any day of the week.
     

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