OT: What's in a USB cable?

[Iain McFadyen]

I have a Standard USB-A to Micro USB-B cable, with a Blackberry logo
stamped on the Micro-B end.

I use this cable for various purposes from time to time: recharging a dumb
cellphone, recharging an FRS radio, and syncing/charging a Blackberry Curve
to the Blackberry desktop software package.

When I leave this cable plugged in to a PC port, but with nothing plugged
in to the Micro-B end, my PC plays up. The cursor hesitates as I drag the
mouse across the screen.

The problem disappears when the Standard end of the cable is unplugged from
the PC.

Question: Is there any active or passive component embedded in this cable?
I see no reason for any components, the VBUS, D+ D- and GND pins should be
wired pin-for pin, and the ID pin at the Micro end should be open, right?

Your thoughts please...

Iain KI4HLV
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