Groups > sci.electronics.design > #446713

Re: USB cabling constraints

From	"Tim Williams" <tiwill@seventransistorlabs.com>
Newsgroups	sci.electronics.design
Subject	Re: USB cabling constraints
Date	2017-02-07 19:06 -0600
Organization	A noiseless patient Spider
Message-ID	<o7dqs5$mg3$1@dont-email.me> (permalink)
References	<o7cpr0$nno$1@dont-email.me>

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The most often committed offense I've seen: incomplete shielding.

Avoid opening the shield at all costs.  Needless to say, a cable like the 
kind with a pin header on one end is useless -- these are most often seen 
between PC motherboard and enclosure, and work only because (and only when!) 
the enclosure is metal.

Connector housings are often taped over with copper or aluminum tape, which 
helps, but it's pretty cheap and unreliable.  (It can be hard to tell, 
because they're usually overmolded.)

Again, needless to say -- housings need to be the metallic shielded kind.

Really, this is just reiterating what's already in the standard, as Jeff 
linked -- but it's worth emphasizing signal quality, especially in regards 
to susceptibility, because this will be the single greatest cause of 
frustratingly intermittent problems, and it can be caused by something as 
passive as a cheap cable.

Tim

-- 
Seven Transistor Labs, LLC
Electrical Engineering Consultation and Contract Design
Website: http://seventransistorlabs.com


"Don Y" <blockedofcourse@foo.invalid> wrote in message 
news:o7cpr0$nno$1@dont-email.me...
> Are there any rules/guidelines for manufacturing/designing USB2
> cable assemblies?
>
> Compared to the constraints on network cables and SCSI cables,
> are they somewhere in-between?  Microphone cables?
>
> Or, more like ZIP cord for speakers?  :>

Thread

USB cabling constraints Don Y <blockedofcourse@foo.invalid> - 2017-02-07 08:43 -0700
  Re: USB cabling constraints amdx <nojunk@knology.net> - 2017-02-07 10:28 -0600
    Re: USB cabling constraints jrwalliker@gmail.com - 2017-02-07 08:54 -0800
    Re: USB cabling constraints rickman <gnuarm@gmail.com> - 2017-02-07 20:37 -0500
    Re: USB cabling constraints Don Y <blockedofcourse@foo.invalid> - 2017-02-07 20:23 -0700
    Re: USB cabling constraints Robert Baer <robertbaer@localnet.com> - 2017-02-08 21:29 -0800
      Re: USB cabling constraints Kamen Lilov <kamenl@gmail.com> - 2017-02-09 14:01 -0800
  Re: USB cabling constraints Jeff Liebermann <jeffl@cruzio.com> - 2017-02-07 10:39 -0800
  Re: USB cabling constraints "Tim Williams" <tiwill@seventransistorlabs.com> - 2017-02-07 19:06 -0600
    Re: USB cabling constraints Don Y <blockedofcourse@foo.invalid> - 2017-02-07 20:35 -0700
      Re: USB cabling constraints "Tim Williams" <tiwill@seventransistorlabs.com> - 2017-02-08 17:49 -0600
        Re: USB cabling constraints Don Y <blockedofcourse@foo.invalid> - 2017-02-08 20:33 -0700
          Re: USB cabling constraints "Tim Williams" <tiwill@seventransistorlabs.com> - 2017-02-09 16:43 -0600
            Re: USB cabling constraints Don Y <blockedofcourse@foo.invalid> - 2017-02-09 16:18 -0700

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