Are you connecting your 4350(USB) device to a bus-powered hub or a self-powered hub? Please read the following:
USB is a multidrop bus, meaning that multiple devices can be connected to the USB bus at the same time. The user can use hubs to add ports to the USB bus. Hubs have one upstream port, which connects upstream toward the host computer, and multiple downstream ports, which connect downstream toward the end peripherals.
There are two kinds of hubs: bus-powered hubs and self-powered hubs. Bus-powered hubs receive all of their operational power from the USB bus, while self-powered hubs receive their operational power from an external power supply, like an AC/DC converter. The typical hub will support both types of operation - that is, with external power and without.
However, the power available on the downstream ports to end devices is less on a bus-powered hub than on a self-powered hub. While this decreased power is sufficient for some low-power devices, like keyboards and mice, it is not enough power to run all USB devices. The result is that if one attempts to connect a National Instruments USB-based device (DAQPad-6020E, DAQPad-6507/8, NI-4350 for USB, NI-5102 for USB) to a bus-powered hub, the operating system will report an error, saying there is insufficient power to run the device.
Solution :
The solution is to supply power to the hub's downstream ports, using a vendor-provided power supply, as specified in the hub vendor's instructions. If there is no option for making a particular hub self-powered, a different hub must be used. Note that USB ports on keyboards - and sometimes monitors - are typically bus-powered. In these cases, a separate, self-powered hub is required. The ports on the back of a computer are, without known exception, always self-powered.
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