OT: USB adapters for PCMCIA slots

[scirocco16vr32 at gmail.com (Chris Bennett)]

Ok it has been my experience that you only have to use the auxillery
power supply for SOME devices.  I believe to meet the IEEE standard it
has to be something like 5v 500mh supplied from EACH port.  You add
the PS to suppliment that for something that draws MORE than 500mh.
You often see USB HUBs that do this.  I commonly run IPOD, thumbdrive,
mice and joysticks off the same port at the same time with a 4port hub
and no additional power supply.  I promptly lose the PS's because I
never have had to use them.  Most USB power hogs have their own
supplies.  I have charged two IPOD in fact off the same hub with out
supplimenting the power now that I think about it.  I have to use a
hub in most cases because the code of the roadwarrier requires me to
carry way more crap than I'd use in a week, much less two days in LA.
LOL

I carry my personal laptop and a work laptop.  The personal has two
ports and I have to use a hub,  To that hub I typically have two IPODs
 (I have a 60gb for music, and a 30gb video for Battlestar Galactica)
charging, a Kensington Trackball, and an external USB Hard drive (has
it's own supply so doesn't count) and I swap out one of those for the
USB Cell Charger.

Anyway WIKI is never wrong (Yea RIGHT)

"The USB specification provides a 5 V (volts) supply on a single wire
from which connected USB devices may draw power. The specification
provides for no more than 5.25 V and no less than 4.35 V between the
+ve and -ve bus power lines.

Initially, a device is only allowed to draw 100 mA. It may request
more current from the upstream device in units of 100 mA up to a
maximum of 500 mA. In practice, most ports will deliver the full 500
mA or more before shutting down power, even if the device hasn't
requested it or even identified itself. If a (compliant) device
requires more power than is available, then it cannot operate until
the user changes the network (either by rearranging USB connections or
by adding external power) to supply the power required.

If a bus-powered hub is used, the devices downstream may only use a
total of four units ? 400 mA ? of current. This limits compliant
bus-powered hubs to 4 ports, among other things. Equipment requiring
more than 500 mA, hubs with more than 4 ports and hubs with downstream
devices using more than four 100 mA units total must provide their own
power. The host operating system typically keeps track of the power
requirements of the USB network and may warn the computer's operator
when a given segment requires more power than is available."

Way more info than I am prepared to process at 9:22 on Sunday AM.

Chris



On 3/31/07, Derrick floyd <tyrone27@gmail.com> wrote:
> I don't think so I think some have a 2 USB with no cable.  Its funny you
> posted this question because I'm looking on e-bay now looking for a PCMCIA
> to USB adapter right now that doesn't take a power supply because I have to
> run 2 serial cables to my laptop Dell latitude CPi-A 266Mhz.  here is the
> one I found:
> http://cgi.ebay.com/Adaptec-1420-2-Port-USB-2-0-PCMCIA-Notebook-Adapter_W0QQitemZ170097128226QQcategoryZ42323QQrdZ1QQcmdZViewItem
>
> On 3/31/07, C Boyko <roccit_53@scirocco.cs.uoguelph.ca> wrote:
> >
> > Okay, I'm sure some of you have had one of these at some point. I thought
> > this would be the magic bullet for avoiding the motherboard issues with my
> > old Dell Latitude, and the cardslot adapter I got has two USB ports in it,
> >
> > which would be really handy, as I only have one presently. So here's the
> > issue. I plugged it in, and read through the instructions, and there is a
> > cable to go into the existing USB port, to power little devices like my
> > externals and iPod charger. Both of these devices are a huge pain in the
> > ass because my USB port is so shaky in its power delivery. And to top it
> > off, the new cable is a "T" shape and with my vertically oriented USB
> > port,
> > the cord needs more room than there is, unless I put the lappie up on a
> > book or something. But the new ports won't light anything up till I run
> > that cable into the old port.
> >
> > So, finally my question, do ALL of these adapters need to be hooked back
> > into the stock USB port for power? I see that there is a cable (*not
> > provided*) that can be plugged into normal AC power instead of the old
> > port, and I may go that route if there isn't a USB adapter for my card
> > slot. Thanks, but this just really pisses me off. It's not like I can just
> > run back to the store to exchange it, it's an hour's drive to get anywhere
> > that sells this sort of stuff.
> >
> > Thanks, you can reply off list if you like and tell me that I'm a hopeless
> >
> > dumbass.
> > cathy
> >
> >
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