Jumper - Mini USB Adapter

Dose anyone know the use of the jumper on the mini USB adapter? i am trying to use it in conjunction with the Arduino mini, connected it up as instructed but cannot get it to communicate with the IDE. Any ideas?

The jumper seems to select whether the 5v from the USB is connected to the 5v output pin.

Since the interface and Arduino Mini don't seem to support automatic reset you will need to do a manual reset when you want to upload a sketch.