Sign in with Sign up | Sign in  The USB Cable Is Out Of Spec!
Is On-The-Go Storage Ready for Primetime?  One connector of the
USB Y-cable is not completely connected, because it serves only
to deliver DC power to the hard disk in the enclosure in the
event that a powered USB port on a PC doesn't deliver sufficient
power to the device (this happens frequently, especially on
notebook PCs). The current draw for most modern 2.5" hard disks
falls in the neighborhood of 0.5 Ampere (500 mA). This value can
momentarily peak even higher when repeated disk reads and writes
occur in a short period of time, or when the drive spins up to
prepare for use. Many USB controllers won't correctly recognize
a hard disk whose power draw exceeds this limit, and that can
lead to subsequent read and write failures. To avoid this
situation and to allow users to drive a USB-attached hard disk
from a computer without an external power supply, many vendors
include a USB Y-cable so it can use two powered ports for
current and data conne