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Posted by Barry Watzman on November 25, 2004, 1:11 am
Please log in for more thread options Re: "It has *two* USB plugs, one for power, one for the data"
More likely, both are used for power. A USB connection can supply only
500ma of power, so some devices that need more than that use multiple
USB connections.
What you really need to do is get an external power adapter for the
drive and use USB for data only.
Alternatively, most USB PC-Cards have an input for an external power
supply, you need 5 volts at not less than 1 amp, with a compatible
connector. Some of the PC-Cards come with such a supply, some don't.
Sometimes they come with a cord to "steal" the power from another USB
port or from a PS/2 keyboard or mouse socket.
If you power the drive from an AC power adapter (wall wart), there's no
reason that you should have to worry about the PC Card. However, I
would not under any circumstances try to feed power INTO a USB port.
Plugging what you call the "power USB plug" into one of the notebooks
USB 1.x ports MIGHT work. I think that the chance of doing any damage
is remote, even if it doesn't work.
But I still think that the best approach is to get a totally separate
power supply for the USB drive (if it has a socket for one) and abandon
the USB connection as a source of power all together.
Markus Dehmann wrote:
> I bought an external USB drive, and it works just fine, *without* a
> Power Adapter. It has *two* USB plugs, one for power, one for the
> data.
>
> Unfortunately, my notebook has only USB 1, so I bought a PCMCIA USB
> 2.0 BusCard (a cheap Syba).
>
> But when I plug the two USB plugs of the hard drive into the PCMCIA
> CardBus, the notebook shuts down immediately! The short manual says
> it's an over current shutdown. It also says I need a power adapter for
> the CardBus if more than one port is used. And for power hungry
> devices, "a DC Power Adapter should also be used at the peripheral
> end."
>
> What, do I need a Power Adapter at the USB drive AND at the PCMCIA
> CardBus??? I mean, it worked just fine without the PCMCIA CardBus
> (just slow) and didn't need any Power Adapter.
>
> But here comes the trick: Can I plug the power USB plug into the
> original notebook's USB 1 plug, and the data USB plug into my PCMCIA
> card? I didn't dare to do it so far. Is that dangerous? Will the
> notebook shut down and/or be broken completely?
>
> Can I get around using an external Power Adapter at all, with the
> PCMCIA CardBus?
>
> Thanks for every hint!
> Markus
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