I found this info on the USB
Pin 1 Red V BUS (5V)
2 White D
3 Green D+
4 Black Ground
5 Joined to pin 4 inside the A plug of a Mini USB cable
Opening facing you contacts down.
The electrical design of USB limits the maximum cable length to 5 metres for full-speed devices and up to 3 metres for low-speed devices. Up to 5 hubs can be connected in series to allow for an extended cable run and up to 127 devices (theoretical limit) can be attached to a single host computer. The hot-swap capability allows a USB device to be plugged in or unplugged without turning the system off. USB devices may be plugged into a USB socket on the PC, into a multi-port USB hub or into a USB device that also functions as a hub for other devices.
The USB 1.1 maximum bandwidth of 12 Mbits/sec is equivalent to a data transfer speed of 1.5 Mbytes/sec with USB 2.0 dramatically increasing this to 480 Mbits/sec.
The USB bus supplies 5V DC regulated power (maximum 500mA) through each port on pins 1 and 4. Low-power devices that might normally require a separate AC adapter can therefore be powered via the USB cable, eliminating the need for associated AC adaptors. Bus-powered hubs derive all their power from the USB bus. Powered-hubs are powered from their own AC adapter and provide better power distribution to downstream devices. Port-switching USB hubs isolate all ports from each other so that a faulty device will not cause all other the devices on the same bus to also fail.
Standard USB plugs and sockets have 4-contacts. Standard USB Type A plugs & sockets are rectangular in shape, with the contact opening measuring 13.1(W) x 5.5(H) mm. The contact opening on standard Type B USB plugs and sockets measures approximately 5.6(W) x 3.2(H)mm.
MINI USB plugs and sockets have 5 contacts with contacts 4 & 5 joined together inside the A plug. The Mini Type A and Mini Type B plugs & sockets are both rectangular in shape, with the contact opening measuring approximately 6.8(W) x 3.1(H) mm. Mini USB cables are also used for USB OTG (Universal Serial Bus On The Go) devices.
.
Steve
tele-dataservices.com