The mobile power supply will have a dedicated input socket for receiving power. This power can come from a USB socket on your computer, but charging may be faster when using a wall socket adapter. We most often see mobile power use Mini or Micro USB sockets for charging and full size USB sockets for discharging. In rare cases, the mobile power supply can use the same socket for input and output, but this is rare, and it should not be assumed that any mobile power supply, because trying to force the power supply to input and output will damage the battery.