need help

[sheera]

Hello friends
This is rajinder singh and I want to know that why usb print servers needs external supply as the usb devices gain their power from device itself like pendrive , bluetooth etc.

 

[AdmnPower]

Typically devices such as flash drives and bluetooth adapters draw very little power, there is a limit to the amount of power than can be supplied to a device through a usb port. When your device exceeds that amount the manufacturer of said device will include a power brick to supply the additional power needed.