At 9:52 PM -0700 5/2/00, [EMAIL PROTECTED] wrote:
>I am attempting to create a power cable for the USB port to power an older ADB
>supplied power device. I am looking at the severed end of my USB cable and I
>see one red and one black "thick" wires, one white and one green "thin" wire
>and one uninsulated wire. Now, like ADB, I know that there is a + and a - wire
>for power and two data wires. Does anyone know which are which? Are 
>the thicker
>insulated wires the power wires or data? Then, which color is +?

Usually, red is positive and black is ground.  But not always.  It's 
a very good guess that the thicker red and black wires are power, 
since they have to carry more current than the signal lines.  Get a 
multimeter and check it.  :)

Be warned that this might not work.  I think USB controllers are 
supposed to be capable of shutting down power to a port, and they 
might not turn the power on if they don't detect a real live USB 
device.  (It may also mess with USB's scheme for allocating limited 
power across multiple devices, though that shouldn't be a problem if 
you always plug it directly into one of the computer's ports.)

>  Finally, is
>the uninsulated wire simply a strengthening cable or is it the ground wire (or
>part of the grounding wiring)? Thanks for any input on this off topic subject.

Could be strength, probably is shield ground, could be both.  Cheap 
cables which only use a thin strip of foil spiral-wound around the 
central insulated wires for a shield need an uninsulated wire up 
against the foil to guarantee that the shield ground is continuous 
throughout the cable, since the foil tears easily.  Better cables 
have foil surrounded by a woven wire sheath.

Since it's most likely a shield (chassis) ground, it would probably 
be a bad idea to try to use it as a power ground.

   Tim Seufert
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