Bryan,

On 5/20/05, BryanW <bryan@purpen.demon.co.uk> wrote:
> Hi,
> 
> I have a laptop, and also have seen problems. I find that the USB ports on
> the laptop do not generate enough power for some of the USB -> Serial
> adapters to work correctly. You get a device is not recognised, and the
> adapter added as a "Unknown USB". I ended up getting a USB self powered hub
> and this got my laptop to detect the adapter correctly. On my Desktop PC,
> there was no problem.
> 
> I have a Toshiba P10 by the way.
> 
> It is not just USB to serial adapters, I have a Nokia datacable that has the
> same problem, which is annoying as I wanted to be able to use this for
> connecting to the net to get my email while out, and an external powered hub
> is not practical for that :(

I was going to say that the USB-Serial adaptor is probably breaching the USB specs for drawing power, but 
seeing your last paragraph I suspect your laptop is either below spec (USB ports should supply 100mA all the 
time, 500mA when it's asked for by the device) or it's been damaged and isn't able to supply the current 
needed.  Any USB port should supply the power as I said, and the fact that a hub sorts it out is the clincher 
that your laptop isn't.  I have seen devices that draw more than they should, but since you have two 
non-functioning devices I think the finger points firmly at the laptop!  Sorry to be the bearer of bad news, 
but it looks like replacing that is the only way you can do what you want.

Cheers,


Howard Winter
St.Albans, England


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