Re: USB questions
- From: Barry Watzman <WatzmanNOSPAM@xxxxxxxxxx>
- Date: Wed, 14 Mar 2007 14:09:38 -0400
The purpose of the USB PC Cards is primarily to "upgrade" a PC that only has USB 1 ports to USB 2 ports, although obviously they can also be used to add more ports as well. The power jack on the cards, when present, is an input, without the input the card doesn't supply power to USB powered devices (in my experience, it doesn't supply ANY power, but in any case, and in no case, can it supply 500ma without an external power source).
"Wall wart" power supplies that are based on switching power supplies rather than transformers are often universal, e.g. 110/220v. That will solve one problem. Also, since what you need is 5 volts (ideally at 500ma per port), supplies are fairly common and you do not need to use the supply, the supply cord or intended source that the card maker suggested ... you only need a 5 volt source with the correct connector (correct connector includes both physical connector and polarity).
The charger cord that you have is a "figure 8" cord, and yes, those are available with different plugs at the wall end. May be hard to find one for any country other than the one that you are currently in, however.
There are lots of cards on E-Bay.
Wow, I've seen a variety of different answers in this thread. Having a
background in hobby electronics, thinking about this these USB
questions, it seems your answer is the one. I do not know what the
voltage to the card bus is, but if 3.3v as you say it is doubtful the
card has an inverter to boost voltage to 5v for USB, never mind
providing 500ma for each of two or four outlets! Furthermore, I know
from experience these DC coaxial 'jacks' (as seen in pictures of the
card) are typically used for power IN, not power out as was stated
previously. In addition, the cables I've seen have a male DC coaxial
connector (to plug into card) and a USB connector on the other end which
leads me to believe the card manufacturers want power IN from another
USB socket. So it looks like I will need an external power supply (wall
Plan on doing an extended stay in Australia this fall (from USA) so I'll
also need some way to plug an American 110v wall plug into an Australian
220v wall outlet. Anybody know where one can be purchased?
Had another idea, this IBM ThinkPad has a charger with a removable AC
cord. Looks to me like one end is universal (sort of an O-O
configuration). Are there AC cords available which have that universal
end with an Australian wall plug on the other end?
Lastly, been looking on eBay for USB PCMCIA cards and USB/Firewire
PCMCIA cards. Any comments on what they're selling there?
"Barry Watzman" <WatzmanNOSPAM@xxxxxxxxxx> wrote in message
If you get a USB PC card that has a power jack, and power that jackfroman external power supply (e.g. a "wall-wart"), it would meet yourwould
requirements. Similarly, a powered hub with it's own power supply
do the job. Of course, you are going to be traveling outside the US,soany such power supplies become an issue unto themselves, as they havetobe plugged into a wall socket that they may not fit, and/or that mightpower
have the wrong voltage.
Another suggestion, are you SURE that your hard drive really needsfrom both (two) usb ports? Just because the cable has the provisiontodo this doesn't mean that it's necessary. In my experience, most 2.5"however,
hard drives will run from a single USB port. You might also get away
with using two USB ports while it's "spinning up" and then unplugging
the 2nd port after the drive is running (this may be a problem,
if the drive is set to "spin down" after a period of inactivity).leaves
none wrote: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
theseno 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
andcards correctly, one needs to power the additional ports from a USB
port! Is this correct? MANY of these cards come with a power cable
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?
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