RE: [Thinkpad] Questions re: external HD enclosures (USB)

Hello,

I agree. The USB info I have seen indicates a 500mA power limit through the bus.
Anything over that must be self-powered. 2.5 Drive specs say around 520mA
average(!) when operating and 800mA to 1100mA maximum during startup.

I suspect some drive enclosure makers get away with bus powered because
some USB ports can provide more than 500mA of current.

I have a nice combo USB 2.0/Firewire enclosure. It is only bus-powered
on the Firewire side because Firewire is spec'd to provide 60 watts of power.
There is a coaxial power jack and a power cable to a PS/2 pass-thru connector
is included. If I did not have a PS/2 jack on the computer I would need a
5 Volt regulated wall wart to plug into the coaxial power jack when using USB 2.0

73 Eric

-----Original Message-----
From: thinkpad-bounces@stderr.org [mailto:thinkpad-bounces@stderr.org]On
Behalf Of Paul A. Pennington
Sent: Tuesday, December 21, 2004 12:33 PM
To: Andrew Webber; thinkpad@stderr.org
Subject: Re: [Thinkpad] Questions re: external HD enclosures (USB)

    Andrew Webber wrote:

> Thanks for any thoughts!

    Spend a few bucks more and get a drive with a wall-wart power supply.
Hard disks draw too much current to draw it from a notebook computer. Check
on CyberGuys:

    www.cyberguys.com

    They have a bunch of this stuff. Mine has removable plastic drawers so
the hard disk drive can be easily changed.

    All USB 2 devices that are correctly built to the specification are
backwards compatible to USB 1.

    PS: Love your musicals.

    Paul Pennington
    Augusta, Georgia

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Received on Tue Dec 21 14:45:51 2004