| Jack Erbes 2008-03-23, 4:33 am |
| P.Schuman wrote:
<snip>
> oops - was thinking the larger normal connectors -
> not the mini - like on cameras...
>
> Here's a link with some connector graphics - the mini has the "5-pin"
> layout.
> http://www.connections-usa.com/usb_pinout.html
> So - it looks like the "x-pin" needs to be connected to ground....
> hmmm - again, wonder how you can tell if the extra 5th "x-pin" is grounded ?
> OR - is the Garmin cable doing something non-standard ??
On the mini-USB the 5th contact is the one that is used to give it a
personality. It is usually done by putting a resistor of a specific
value from the "x" lead to the power ground. Of course, the device has
to have the internal hardware and software to read that resistor value
and decide what to do. If you plug the "special" cables into something
that does not use the 5th lead I suppose that it just acts like a
regular mini-USB cable.
Here is a place with a little more info on the Garmin cables:
http://pinouts.ru/GPS/ garmin_nuvi_...r />
nout.shtml
Looking into a mini-USB plug, the five pins are 1 2 3 x 4
If the above link is right, a standard cable has a 200K Ohm resistor
between x and 4 and a Garmin cable has a much lower value resistor, like
17K Ohm to 22K Ohm or so.
Jack
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