Sony PCV-R553DS - Manual (Page 72)

VAIO Digital Studio™ Reference Manual 58
USB Connectors
There are two USB ports that permit connection of two USB peripheral
devices directly to the system without having to use an external hub.
USB2 is a standard USB connector accessible from the rear panel.
USBHEAD is a 4-pin single-line header that connects to a standard USB
connector (USB1) accessible at the bottom of the front panel. An internal
cable connects USBHEAD to an interface board behind the front panel.
If more USB devices are needed, connect an external hub to either USB1
or USB2.
USBHEAD (connects to USB1 on front panel)
Pin
Signal Name
1 USBVCC2
2 USBP1#
3 USBP1
4 Ground
KY0033.VSD
USB2
USBHEAD
(connects to USB1
on front panel)