EASY USB question

I have a PII MMX 400 mhz system with 2 USB ports at the back.

I am told that USB can take up to 28 or so devices via a daisey chain.

How do I obtain this daisey chain thing, how much cost and is it bulky?

Also what devices are now available on USB and do more of them added together slow the processor down.  I also have a SCSI UW card, should I use that instead?

I have a USB Intel web camera so far.

Please add to the list the available devices.

Camera
Scanners
Monitors????
Hard drives????
ey143Asked:
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khemicalsConnect With a Mentor Commented:
USB theoretically can handle up to 127 devices total. I believe the current record is 111 devices at COMDEX in Las Vegas.

what you need to connect multiple USB devices together is a USB hub. These devices can be found at your local best buy or comp usa or whatever you have in your area... however USB keyboards and monitors tend to have built in USB hubs... some devices also have pass thrus... so it all depends on what you want and need. cost also depends on what you want and how many ports on the hub or device, etc etc... but about 50-100 seems to be market

USB pretty much supports all computer devices just as long as someone makes a device that can use USB... the following is directly from Intel's USB page (www.intel.com/design/usb) :
Q3: What kind of peripherals will USB allow me to hook up to
                       my PC?
                       A3: You name it: telephones, modems, keyboards, mice, 4x and 6x
                       CD ROM drives, joysticks, tape and floppy drives, scanners and
                       printers. USB's 12 megabit/s data rate also accommodates a whole new
                       generation of peripherals, including MPEG-2 video-based products,
                       data gloves and digitizers. Also, since computer-telephony integration is
                       expected to be a big growth area for PCs, USB can provide an
                       interface for Integrated Services Digital Network (ISDN) and digital
                       PBXs.

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ey143Author Commented:
Sorry for the delay.
Thats quite interesting thx.

Am I right in thinking (having read the above) that keyboards now have an input device for another USB port too so that I can basically connect my USB joypad/mouse into THAT, INSTEAD of into a USB port in the computer?  If that is the case, then obviously it will save me buying another USB expansion hub?  How many ports will a keyboard have, and will it cost much?

Finally, isn't it a waste of money using a USB keyboard for a single USB port when speed is more important and instead you could use the USB port for a scanner or CD-WR?  Why waste it on a connection only.


VER VERY finally, USB only refers to external equipment doesn't it?

Thx.
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ey143Author Commented:
I also forgot to ask, can it provide that much electric power even to a Forcefeed back joystick from Microsoft, so that I dont need to connect the joystick to the main electrical socket?  How much will 500ma get you?
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khemicalsCommented:
some USB keyboards, or rather most have integrated USB hubs on them for convinience. and yes you could use those instead of a regular USB hub. # of ports i have seen is basically 4... but ofcourse it could be whatever number the manufacturer chooses.

I don't understand what you want to know about the CD-RW stuff... you may either want to clarify that or rephrase it. 500ma will get you as far as the devices will allow. this is completely dependent on  the individual devices... so for this info you would need to contact the manufacturer...

i have a feeling most of your questions are a matter of are they a standard or not... the page i gave you earlier spells out the standards, and the rest is up to the manufacturer, so read up on the devices that interest you and that will probably get you what you want to know
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ey143Author Commented:
What I meant was when I was referring to CD-RW, was that, is USB used for only external devices? The report on the link you provided said there will be no more problems with IRQ conflicts etc, but then graphic cards, sound cards, they all need to be installed in a PCI slot, which still works on IRQ.

Any idea of cost for a keyboard with USB ports?  I looked at websites which do not list the price, and I have not seen any here in the UK.


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khemicalsCommented:
I have never heard of any internal USB devices, however that does not mean there are not any... and certainly there is no reason that an internal USB device would not be feasible.

The idea is that all devices on the USB chain will not have IRQ conflicts, not all the devices in the system, however it is a positive step towards that. Not all devices need an IRQ that are on the PCI bus, for example, the ATI Xpert@Play video card does not use an IRQ along with several other video cards.

Last time I saw a USB keyboard it was somewhere around 50-70 USD.

your best bet would be to call a vendor and ask for a price as prices on the newest technology tend to change rapidly.
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ey143Author Commented:
How would an internal USB device plug into the external USB port.  That would surely defeat the whole point of using PCI or ISA?
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khemicalsCommented:
as of now you would need to drill a hole into the case... again all of my answers are based mainly upon current technology.... but some of it has to be left open w/o answers as who knows where it will go. I was not saying that there are internal USB devices but simply stating that someone could design one.
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ey143Author Commented:
Cheers.
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