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A short discussion and a couple of USB questions

 

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Hello:

I am Ken Gordon, am now 82 years old, and have been involved in electronics since I was 13 years old in 1956.

So, recently I have been involved in "Elmer-ing" a good friend who is not particularly adept at electronics.

I have been helping him get his ham station operable on digital modes. He bought a new Acer laptop to use for these modes. While trying to get Fldigi installed, we discovered that his Acer laptop's USB ports' two data lines are reversed from all others we have dealt with up to this time: i.e. Data - (minus) and Data + (plus) are "reversed" in his new machine.

This, apparenty, doesn't matter when those lines are used for USB devices such as a mouse or a USB powered CD drive, but that DOES matter when those data lines are used to pass audio to/from the computer to the digital interface (in this case either a SignaLink or a DRA device).

I thought it might be easiest for me to make him a short jumper cable out of a short USB extension cable by cutting it, and "cross-wiring" those two data lines.

However, upon opening the cable, I find not 4 (or 5) wires, but a total of 11, 3 of which are obviously grounds.

I have not yet been able to "ohm-out" the wires vs connections since I must make a needle-point adapter for my VOM, but in the meantime, here are the wire colors.

First, separate black, white, green and red. These should be the standard + and - 5 V and Data + and Data -

But there are two "bundles" of other wires, These "bundles" contain a slim bare wire and two other thinner wires, pink and purple in one "bundle" and blue and yellow in the other.

Might anyone here have a clue as to what these are, or how they are wired?

Ken Gordon W7EKB

Virus-free.
wn4isx
 

My primary radio and lab PC are HP Elitebooks and each needed to communicate with USB devices, SDR radio, USB oscilloscope, a USB capable DVM. The PCs are on a narrow shelf with no room for regular USB-A connectors so I purchased 6" USB extensions off Amazon (or Ebay, it's been 4 years).
I needed a USB breakout box so I used one of the spare 6 inch extensions, cut it in "half" and wired it to a scrap piece of Veroboard with turrant style "pins"
The grounds and V+ go to single pins, the data V-/V+ go side by side pins located 1/10" appart with solid 22AW tin plated copper wire. This way I can look at the normal data on a scope, and, if needed, intercept it.
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I was hoping to troubleshoot a Bearinger USB audio interface that will occasionally get confused and lock up.
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Clearly I don't know enough and the plan was a bust, but these cables had
Shield (aka drain)
Black V-
Red V+
Twisted pair
Black Data V- Standard is green?
White Data V+ Standard is white
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This is similar to what I found.
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You might want to try another cable, go a used thrift store, you can pick up USB cables for a dollar or less.
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A lifetime ago I intercepted RS-232C data from a data terminal to satellite control system to "Roll my own
?terminal program." I'd hoped USB would allow similar data sniffng, but you clearly have to know exactly what you are doing to examine the data packets between a PC and device.
It was? a useful lesson in the limits of my knowledge.
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I eventually learned the original drivers for the USB audio device were buggy, V2.0 solved the problem.
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USB won't tolerate much extra electrical imbalance and, if the motherboard is set up to use the data lines backwards, the pull up resistors might cause trouble.
Intel has several detailed papers on USB
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USB 3 wiring is very diferent from USB 2
I've never messed with the wires in a USB 3 cable.
You can generally use USB 2 cables on a? USB 3 port but not always. My wife's Dell Opttrash Windows 10 PC has 2 USB 3 ports, one works fine with USB cables, the other only works with USB 3, the user manual doesn't mention this and Dell tech support is non-existent.
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wn4isx
 

I meant to add, are you sure you have genuine USB chips? There are a lot and I mean many counterfeits on the market that almost work right. Look up USB FTDI fake or counterfeit.chips. The fakes can cause all sorts of problems, And they show up in respected units.
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I think there are programs to examine your chips to determina "Real/fake."
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Ken:

Does this help?
in the description.





--
G.T.


--
G.T.
 

Ah USB 3 has the same 4 wires as USB 1 & 2 plus 4 extra ie 2 twisted pairs, sort of thing used for differential and screened too ie very high speed.
 

On 28 Dec 2024 at 10:34, Gooey via groups.io wrote:


Ken:

Does this help?
Look at the fifth image in the description.
Yes. It does. That photo tells me that what I am trying to work with is a HighSpeed cable, and
that what I need is a simple standard cable.

That photo is exactly the same as the cable I am working with. There are two "extra" pairs of
shielded wires included in that cable. Although I don't know this (yet) for certain, I suspect
those are wired in parallel with other standard wires, possibly the data cables.

I'll find out soon enough.

I will also go to one of the local "surplus" stores and try to find a standard low-speed cable.

Thank you for the photo.

Ken Gordon W7EKB



--
This email has been checked for viruses by Avast antivirus software.
www.avast.com
 

On Saturday 28 December 2024 03:15:39 am wn4isx via groups.io wrote:
A lifetime ago I intercepted RS-232C data from a data terminal to satellite control system to "Roll my own
terminal program." I'd hoped USB would allow similar data sniffng, but you clearly have to know exactly what you are doing to examine the data packets between a PC and device.
It was? a useful lesson in the limits of my knowledge.
Have you looked at that little analyzer that I mentioned a while back? Check out sigrok.org, the thing cost me under $20 and has a *LOT* of different protocols that the software (pulseview) understands. The video at details what the thing can do in one specific instance, I2C. Take note when he hits the dropdown that allows you to select which protocol you want, USB is in there.

Mine is a different brand than the one he got, but it's otherwise the same. Yes, you can do USB sniffing to find out what's going on.

You should get one of those. :-)


--
Member of the toughest, meanest, deadliest, most unrelenting -- and
ablest -- form of life in this section of space, ?a critter that can
be killed but can't be tamed. ?--Robert A. Heinlein, "The Puppet Masters"
-
Information is more dangerous than cannon to a society ruled by lies. --James
M Dakin
wn4isx
 

In my situation, just about the time I was ready to order an analyzer software package the company came out with V2.0 drivers which solved the problem.?
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