I recently acquired a Samsung Focus along with an AT&T Zero charger and, in order to qualify for a discount that more than made it free, added an AT&T branded extra Micro-USB cable to the lot.  For those unfamiliar with the AT&T Zero it is a USB charger that detects when there is no device actually being charged and stops using power.  So unlike standard chargers there is none of the so-called “vampire” power usage.  When I returned home I installed the Zero charger in the power strip under the bed with a Micro-USB cable going from it to my nightstand.  I then went downstairs with the other Micro-USB cable and Focus in hand to sync it with my PC.  Sounds simple enough, right?

Well, it wasn’t simple at all.  When I first plugged in the Zero and cable I noticed that the little blue light on the Zero did not go out.  I figured that while I was syncing the Focus I could research what that meant.  Then when I plugged the Focus into my PC no drivers loaded (or as others might see it, the Zune Desktop couldn’t see the device to sync it).  I tried to research both why the Focus wouldn’t sync with Zune Desktop and what the blue light on the Zero staying on despite no device being attached meant.  In both cases I couldn’t find a definitive answer, but lots of hints that it was something to do with Micro-USB cables.  So I swapped my two around and sure enough both problems were solved.  Plugging in the cable from the Focus to my PC causes Windows to load the driver for it and the Zune Desktop to see the device.  Plugging in the other cable causes the Zero to shut off when there is no device attached and then on to charge when a device is attached.

What I didn’t realize is that there are two types of Micro-USB cables, Power+Data and Power-Only.  There are no markings on the cables to make it easy to tell them apart, though if you are holding them next to one another you’ll notice that the Power+Data cable is thicker than the Power-Only cable.  The Samsung Focus comes with a Power+Data cable while the extra Micro-USB cable sold in the AT&T store (and most likely the ones that come with feature phones and other non-syncing devices) are Power-Only cables!

It turns out I initially had tried to use the Power-Only cable to sync the Focus and the Power+Data cable with the Zero.  Now I fully understand why you can’t sync with a Power-Only cable 🙂  But why does the Zero fail to shutoff when a (this?) Power+Data cable is used? 

The bottom line for syncing the Samsung Focus with Zune Desktop is easy, make sure you are using a Power+Data cable.

The bottom line for making sure your AT&T Zero operates properly is that there is no simple bottom line.  I don’t know, for example, if the problem I had was a problem with all Micro-USB Power+Data cables or is something non-standard about the Samsung cable.  I do know that the Zero works fine some other (non-Micro) Power+Data cables I had around the house, such as the one that comes with the iPhone.   I also know that when I plug a Mini-USB cable into it that works, but when that cable is then plugged into an iPhone dock the Zero sees a device (even though there isn’t one in the dock).  So the only bottom line I can come up with for the Zero is caveat emptor.  The Zero may or may not work for your particular application and AT&T doesn’t provide enough information for you to figure it out in advance.  I’m glad I got mine to work…the energy expended (driving) to return it would have exceeded the energy it could save in my lifetime.