I have taken a cheap Amazon Basics USB 2.0 Hub and have started soldering wires on it with a USB C plug breakout I bought from Pololu

I soldered the Vbus, Gnd, D+ and D- respectively from the USB C to where the Upstream USB A is on the hub and while the power is working fine, the Data pins don't seem to communicate effectively. I think this has to do with the fact of using a random wire to do this which might not be impedance matched (or something along those lines) but I have no idea how to debug this and solve the problem.

I am not trying to plug both the A Male and the C at the same time, just left them there both for testing. The A male plug still works fine but my C plug won't transmit data correctly. I already checked if based on the sloppy soldering anything was shorted and all connections are good.

While what I want is for this to work, I also don't know how to debug this so any help or hints into what to try to find the issue and fix it is greatly appreciated.


simulate this circuit – Schematic created using CircuitLab

USB C Wire Soldered on the Bottom

Top view from USB A Male Cable

Soldered Breakout Board

  • 1
    \$\begingroup\$ What do you mean by a "splitter"? Can you share a schematic of what you built? \$\endgroup\$
    – The Photon
    Nov 25 '18 at 2:48
  • \$\begingroup\$ @ThePhoton Just removed that part because it's not really relevant. Sorry for misleading you. The tl:dr is I want to change the upstream USB A to an Upstream USB C for now, but the Data pins aren't working. \$\endgroup\$
    – Mr. Adobo
    Nov 25 '18 at 2:55
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    \$\begingroup\$ Can you share a schematic of what you built? "I just started soldering wires onto it" doesn't tell us much about what you built. \$\endgroup\$
    – The Photon
    Nov 25 '18 at 3:06
  • 1
    \$\begingroup\$ Click on the schematic button while editing your question and you can use the built-in editor. It's not perfect for this situation, but will do the job. \$\endgroup\$
    – The Photon
    Nov 25 '18 at 3:19
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    \$\begingroup\$ As long as you don't connect both the USB A and USB C at the same time, this could work in principle. Are you trying to use it at Full Speed (12 Mb/s IIRC) or High Speed (400 Mb/s)? How long are the wires from the original circuit to the USB C? (A photo might help) \$\endgroup\$
    – The Photon
    Nov 25 '18 at 3:34

There are two fundamental problems with this re-work:

  1. You cannot use "speaker wires" to transfer USB signals. If anything, you should use a piece of standard USB cable for this. USB data lines must have 90 Ohm (+- 15%) differential impedance to work properly. You can't debug this and the only solution is to use proper USB 2.0 cable (which has D+/D- as a shielded twisted pair), and make soldering ends as short as possible.

  2. You cannot "split" the connection and keep your old cable. It means that you need to cut off your old cable, you can't have a fork on USB data lines. Hanging ends of cable will produce horrible signal reflections, and USB doesn't like it at all.

To debug the USB connectivity issues you need a USB protocol analyzer, something like Teledyne-Lecroy Mercury T2, or Total Phase Beagle 480, or Ellisys Explorer 260, which run for $500-$1000, or maybe some cheaper clones from Alibaba or eBay.

  • \$\begingroup\$ Would you suggest splicing the A end and then attaching my C breakout on the spliced ends? \$\endgroup\$
    – Mr. Adobo
    Nov 25 '18 at 6:40
  • \$\begingroup\$ @Mr.Adobo, yes, this would be a solution. Just make sure that both R1 and R2 resistors are soldered. More, since you are using Type-C receptacle (not plug), you need to use both sides of connector A6+B6 for D+, and A7+B7 for D-. \$\endgroup\$ Nov 25 '18 at 6:47
  • \$\begingroup\$ Thankfully the breakout board I got handles all that. I'll give this a shot now. Thanks for the input! \$\endgroup\$
    – Mr. Adobo
    Nov 25 '18 at 6:51

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