http://www.ni.com/pdf/manuals/373506e.pdf
Page 7
The NI 9411 also has a 2-terminal screw-terminal connector that provides connections for an external power supply.
If you do not have a 5 V power supply to directly power the external device or if you want to simplify wiring, you can connect an external power supply to the Vsup and COM terminals on the NI 9411 screw-terminal connector, and connect the external device to one of the 5 Vout pins. If the external device is already powered, you do not need to connect a power supply to the NI 9411 or connect the +5 Vout pin to the external device.
