Hi,[QUOTE=ellentk;2525714]I’ve got an old laptop with usb 1.1 capability.
I added a 2-port usb 2.0 pcmcia card,
which works fine for flash drives and my
mp3 player, but now i need to add
an AC powered hub to run a dvd burner
(asus sdrw-08d1s-u). xp recognizes it
sometimes, usually w/o a disc inserted.
i figure the old laptop just can’t power it.[/quote]I guess, this drive did not come with a power supply. Correct me, if I am wrong.
Bus powered optical drives do not comply with USB specifications.
By specification, an USB port provides 500mA @5V on device request.
Slim DVD writers have a power rating of 1500mA @5V. Connecting such a thing to an USB port causes heavy overload which in a worst case scenario can damage the USB port irreversibly.
This Asus drive is even more evil. I found a photo of this unit. The sticker on the back mentions a rating of 2000mA @5V
With Cardbus USB adapters, there is an additional difficulty:
These often are not able to supply the 500mA without additional power feed. That’s why these cards normally have a power terminal, that can be fed either via a PS2 port, an USB port or an external power supply.
But still then, the adapter must not necessarily be able to handle a 200% overload.
does it matter if i connect the hub to one of the 2.0
ports on the pcmcia card or to one of the
1.1 ports on the laptop? would their be
a speed or reliability difference?
An USB hub can be some kind of workaround, but still, nobody can tell you if it can deal with non-compliant devices. If you want to try that, connect it to your USB 2.0 adapter. USB 1.1 is not fast enough to feed a DVD writer properly.
The best option is to return the external slim drive and get one that comes with a sufficient power supply.
External DVD writers without power supply are designed to be sold, and not designed to work.