I got a USB wire from an old mouse and the wires were soldered to the circuit as: Green - D, Orange - C, Blue - V and White - G.
Assuming orange was red and white was black; they should be VCC and GND respectively. Meaning they transmit power. enter image description here

However I found that the green and blue writes could power a LED, with blue being positive and green negative. The other two couldn't.
I don't have a voltmeter to check so I was wondering whether the wires were mixed up or if this is normal. If the wires are mixed up, how do I separate D+ from D-?


  • \$\begingroup\$ Take a multimeter and ring them from the pins. \$\endgroup\$
    – Eugene Sh.
    Aug 4, 2015 at 17:35
  • \$\begingroup\$ @EugeneSh. Umm. Could you elaborate on that? (Sorry) \$\endgroup\$
    – Rhaegar
    Aug 4, 2015 at 17:49
  • 3
    \$\begingroup\$ Set your meter on the "beep" thing (continuity testing. If you don't have it, just use the ohmmeter to check for low resistance), then open a pinout diagram of a USB connector and check the continuity between the pins and the wires, such that you establish the true correspondence. \$\endgroup\$
    – Eugene Sh.
    Aug 4, 2015 at 17:51
  • \$\begingroup\$ Data, Clock, Voltage, Ground. Sounds like a throwback to PS/2 mice. \$\endgroup\$ Aug 4, 2015 at 19:05
  • \$\begingroup\$ If you are going to power a LED from USB, remember to put an appropriate resistor in series with the LED to limit current. \$\endgroup\$
    – vaizki
    Feb 2, 2022 at 12:17

1 Answer 1


This is the pinout (from the Wiki page)

enter image description here

Simply check continuity with your multimeter, as Eugene Sh says, and ignore whatever wire color code they happen to have used.


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