Micro USB cables that only charge but no data, no mounting etc (Samsung Galaxy S) Not all cables seem to be created equal but I've never got to the bottom of why so many (cheap) cables I try only charge - no data. Anyone know why? Certain pins not connecting?

I do know that longer cables or car to usb converters fail to transmit enough power for the phone to register and not charging but I'm getting the opposite. I don't think I am alone (same problem for Nexus One users here)
Broadly speaking, if you have a "USB" cable that only connects pins 1 &amp; 4 then you will get power and no data (Best Buy was selling cables like that as Universal USB Charging Cables a while back, not sure if they still do). Likewise, if you have a cable with only 2 &amp; 3, you will get data but no power. If you're curious, here's a Wikipedia page with the standard USB Pinout. 

Note: Micro uses the same pinout as USB A.