no sera la mejor respuesta, pero se que se puede sacar solo 5 volts
Pinout
_________
l_4_3_2_1_l
______
l 1 2l
l l
l_3___4l
Series "A" plugs are used towards the host system and series "B" plugs are used towards the USB device.
Pin Name Description
1 VBUS +5 VDC
2 D- Data -
3 D+ Data +
4 GND Ground
Features:
* True Plug'n'Play.
* Hot plug and unplug
* Low cost
* Easy of use
* 127 physical devices
* Low cost cables and connectors
Bandwidth:
* High speed: 480 Mbps speed (in USB 2.0 and above)
* Full speed: 12 Mbps speed (requires shielded cable)
* Low speed: 1.5 Mbps speed (non-shielded cable)
Definitions:
USB Host = The computer, only one host per USB system.
USB Device = A hub or a Function.
Power usage:
Bus-powered hubs: Draw Max 100 mA at power up and 500 mA normally.
Self-powered hubs: Draw Max 100 mA, must supply 500 mA to each port.
Low power, bus-powered functions: Draw Max 100 mA.
High power, bus-powered functions: Self-powered hubs: Draw Max 100 mA, must supply 500 mA to each port.
Self-powered functions: Draw Max 100 mA.
Suspended device: Max 0.5 mA
[edit] Voltage:
* Supplied voltage by a host or a powered hub ports is between 4.75 V and 5.25 V.
* Maximum voltage drop for bus-powered hubs is 0.35 V from it's host or hub to the hubs output port.
* All hubs and functions must be able to send configuration data at 4.4 V, but only low-power functions need to be working at this voltage.
* Normal operational voltage for functions is minimum 4.75 V.
Shielding:
Shield should only be connected to Ground at the host. No device should connect Shield to Ground.
Cable:
Shielded:
* Data: 28 AWG twisted
* Power: 28 AWG - 20 AWG non-twisted
Non-shielded:
* Data: 28 AWG non-twisted
* Power: 28 AWG - 20 AWG non-twisted
Power Gauge Max length
28 0.81 m
26 1.31 m
24 2.08 m
22 3.33 m
20 5.00 m
Cable colors:
Pin Name Cable color Description
1 VBUS Red +5 VDC
2 D- White Data -
3 D+ Green Data +
4 GND Black Ground
si lo quieres ver mejor aqui esta el lnk hacia el "harwarebook"

http://www.hardwarebook.info/Universal_Serial_Bus_(USB)
y aqui tienes un explicacion muy detallada de la historia y funcionamiento del usb
http://www.zator.com/Hardware/H2_5_3.htm
esperoque te sirva la info!