This is a charger dock type, IE, is used as support to put the phone and battery charge or access to data.
There was a time that phones use these docks to make scheduling and timing commitments. This today is nonsense, because all Android using the 3 g or WiFi to do this Google servers automatically. Even so, It's still comfortable to put your phone into a dock for loading.
There's a micro USB connector in position that would fit perfectly on a Samsung Galaxy S2 i9100. I say fit since I don't have a S2.
But in DealExtreme I found a user who bought and guaranteed that works. Check the photo from his cell phone:
On the back you connect the micro-USB cable that comes with the phone. The other side can be on the computer or in the source.
Actually, I bought this dock to try to use in my Jiayu G3, what didn't work for 2 2 motives: the G3 is greater than the S2 a few millimeters and not embedded, and in addition the G3 connector is unlike, What would the phone be back to the dock.
I'm still looking for a dock to the G3, But if you have a Samsung S2 can buy this I found on DealExtreme. Link below:
http://dx.com/p/mini-charging-dock-station-for-samsung-i9100-black-117,368