Re: USB questions

Most USB PC Cards supply ***NO*** power unless an external supply is connected. Not even 100ma. USB PC Cards must operate the PC Card slot in the "cardbus" mode, and in that mode the power to the slot is 3.3 volts, not 5 volts.


M.I.5¾ wrote:
"none" <nospam@xxxxxxxxxxxxxxxx> wrote in message news:nTGJh.4744$B25.7@xxxxxxxxxxxxxxxx
I'm preparing for travel overseas and this will be a first with a
laptop. I have an external HD powered by the TWO USB ports which leaves
no other USB ports, and I need at least one more port. Thought about
buying a PCMCIA card with expansion ports but if I'm understanding these
cards correctly, one needs to power the additional ports from a USB
port! Is this correct? MANY of these cards come with a power cable and
it appears all the PCMCIA cards have a jack for power! Doesn't the
expansion card provide its own power to the additional USB ports?


The PCMCIA card will supply 100 mA per port (as indeed will a bus powered hub). If you require more (up to 500 mA per port) then an external supply needs to be provided. Most (but not all) PCMCIA USB cards come with a suitable supply.


.

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