Quote:
Originally Posted by vermaden
What is the difference, TWO USB cables OR TWO cables one being USB and one power?
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If the power required by a USB device requires more power than the USB specification provides, there are three choices:
- Get the needed power from a wall outlet. This assumes a wall outlet is available.
- Get the needed power from yet another USB connection given that the USB specification states that x amount of power will be available to each attached device.
- Don't use the device since it requires more than what the USB specification makes available.
Scenario: if one is in a park with a laptop & stores stuff on an external USB hard drive, having two USB connections back to the laptop allows the hard drive to be used. USB hard drives with a wall plug brick will be of little use in such a situation.
Yes, this may seem to be a contrived case, but apparently enough people see this as a viable solution that a number of products can be bought implementing this solution. As for me, less space is required in a laptop bag for this solution as opposed to also carrying around a wall outlet power brick forcing me to only use the drive when I am in the proximity of an outlet.
Convenience is what drives this being commonly available in the marketplace.