392
Its braided (thelemmy.club)
submitted 7 months ago by [M] to c/iiiiiiitttttttttttt@programming.dev
44 comments fedilink hide all child comments
 
you are viewing a single comment's thread
view the rest of the comments
[–] 58 points 7 months ago (11 children)

Sure, a long as those cables are shielded. Crosstalk was a real thing "back in my day".

  • permalink
  • fedilink
  • source
  • hideshow 11 child comments
    •
  • [–] 17 points 7 months ago

    It still happens, the modern standards just handle these impairments better with line coding, active equalization, and more sensitive modem electronics. And obviously now we have shielding requirements in the PHY for 2.5G and above. But basically as DSP got cheaper and more compact, they were able to throw more compute at the problem which made a huge difference.

  • permalink
  • fedilink
  • source
  • parent
  • [–] 7 points 7 months ago (8 children)

    I don't think I've seen a single data cable that didn't have some kinda shielding since the early nineties.

  • permalink
  • fedilink
  • source
  • parent
  • hideshow 8 child comments
    •
  • [–] 21 points 7 months ago* (last edited 7 months ago) (5 children)

    Most ethernet cable is UTP, literally "unshielded twisted pair." Shielded cable is much more expensive and less physically flexible due to the metal jackets, so people dont tend to buy it by default.

    You can argue the jacket is shielding, but mostly ethernet cable is not shielded. The braiding will cause problems, but likely very minor ones based on the length of the the run that CRC will compensate for.

  • permalink
  • fedilink
  • source
  • parent
  • hideshow 5 child comments
    •
  • [–] 3 points 7 months ago (3 children)

    Would the twisted pairs prevent cross talk between two separate cables like it does individual wires?

  • permalink
  • fedilink
  • source
  • parent
  • hideshow 3 child comments
    •
  • [–] 6 points 7 months ago (2 children)

    Yes, in theory. But in practice it depends on the frequencies.
    Even if interference is insignificant, looping the wires around a metal core (which braiding does) creates a different impedance and can degrade the signal.

  • permalink
  • fedilink
  • source
  • parent
  • hideshow 2 child comments
    •
  • [–] 2 points 7 months ago (1 child)

    Get out! From the inductance? How long it a length of wire does it take for that to become an issue?

  • permalink
  • fedilink
  • source
  • parent
  • hideshow 1 child comment
    •
  • [–] 7 points 7 months ago

    It's the wrapping of it around a ferrite core that does it. Surprisingly little can make a difference at certain clock rates. If you take a cat5 cable running 1G and loop it a dozen times in a 6" circle and put a metal screwdriver perpendicular to the loop in its center, you will see a spike in bit errors. Weaving one wire with another isn't going to be as strong of an effect, and it's fiendishly complicated in terms of an e/m problem, but it could easily be significant.

  • permalink
  • fedilink
  • source
  • parent