• Re: Flat Ethernet cables - what is that about?

    From Andy Burns@21:1/5 to David on Sun May 19 20:08:54 2024
    David wrote:

    Back in ancient history network cables had to be twisted to stop interference.
    I think.

    Now Ethernet cables are sometimes flat.

    Doesn't mean they're not twisted pair ...

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  • From David@21:1/5 to All on Sun May 19 19:04:34 2024
    Back in ancient history network cables had to be twisted to stop
    interference.
    I think.

    Now Ethernet cables are sometimes flat.
    Is this a new thing?
    Is it because both ends can cope with more interference?

    Just idly puzzling.

    Cheers



    Dave R



    --
    AMD FX-6300 in GA-990X-Gaming SLI-CF running Windows 10 x64

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  • From Abandoned Trolley@21:1/5 to David on Sun May 19 22:49:33 2024
    On 19/05/2024 20:04, David wrote:
    Back in ancient history network cables had to be twisted to stop interference.
    I think.

    Now Ethernet cables are sometimes flat.
    Is this a new thing?
    Is it because both ends can cope with more interference?

    Just idly puzzling.

    Cheers




    I had a NAS box about 15 years ago (possibly called a Buffalo
    LinkStation) which came with a flat Ethernet cable - so its definitely
    not a "new" thing

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  • From Theo@21:1/5 to David on Sun May 19 23:12:55 2024
    David <wibble@btinternet.com> wrote:
    Back in ancient history network cables had to be twisted to stop interference.
    I think.

    Now Ethernet cables are sometimes flat.
    Is this a new thing?
    Is it because both ends can cope with more interference?

    Just idly puzzling.

    Pairs are run close together to minimise the area of the inductive loop the signal current flows around (transmitter+ => wire+ => receiver => wire- => transmitter-)

    In an external magnetic field, the induced curent is proportional to the
    loop area. Make the loop as small as possible => small induced current => minising interference from induction

    Twisted pairs are a way to achieve a very small loop area - the tighter the twist the smaller the loop. They also take out imbalances, eg one wire
    being closer to the edge of the cable than the other.

    Some flat cables have the pairs twisted, so all is fine.

    On those where the pairs aren't twisted, they're run in parallel. The loop area is still kept small, but there's a risk of unbalance, eg capacitive crosstalk from wires in adjacent pairs. To remedy this they are kept short (capacitance is proportional to area of the plates - length of adjacent
    wires in this case). They are just patch cables, and not used for wiring up
    an office block.

    Theo

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  • From Jeff Gaines@21:1/5 to All on Mon May 20 07:11:53 2024
    On 19/05/2024 in message <v2ds5c$3j0l6$1@dont-email.me> Abandoned Trolley wrote:

    On 19/05/2024 20:04, David wrote:
    Back in ancient history network cables had to be twisted to stop >>interference.
    I think.

    Now Ethernet cables are sometimes flat.
    Is this a new thing?
    Is it because both ends can cope with more interference?

    Just idly puzzling.

    Cheers




    I had a NAS box about 15 years ago (possibly called a Buffalo LinkStation) >which came with a flat Ethernet cable - so its definitely not a "new"
    thing

    My Buffalo Terastation introduced me to a flat Ethernet cable as well!

    --
    Jeff Gaines Dorset UK
    All those who believe in psychokinesis raise my hand.

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