[mdf-occ1]

My computer, or I should say Keyboard, has been doing some funny things. The keyboard has been completely crappin out on me. It won't respond to a thing! This only happens once in a while, but enough to make it somewhat a concern. I'm running a B&W G3 with, of course, 2 USB ports on it. In one port is the USB Extension that connects to the Keyboard (Standard Apple USB), and the other is my joystick. From the keyboard, I have my Intellimouse and also a scanner hooked up to it. I know it sounds weird that a scanner is connected to my keyboard, but that's the way it fits on my desk.

Now my question is, does USB have a maximum amout of power it can draw, then it shuts something off?

Also, is there any utility to see the power consumptions from USB devices?

BTW, the scanner is new, and so is this problem, so maybe it has something to do with it?

Any help is very much appreciated!

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mdf-occ1
Mad Skillz Homie Dawg

[This message has been edited by mdf-occ1 (edited 03-03-2000).]

[Don Foy]

Yes, the scanner is the problem, or at least it is most likely the problem.
USB has a certain power that it provides to devices. Most scanners exceed the power that is provided by the hub that is built into the keyboard.

It works this way. The two ports on the mac function as powered outlets. They support a certain level which is probably included in your documentation (I'm too lazy to look it up right now). The keyboard is hooked to one of those, and it draws power. It als acts as an unpowered hub, with one port on either side. The mouse on the right draws power as well. When you added the scanner, you exceeded the voltage and it starves other devices of power. That, as you have seen, causes problems.

You have a couple of options. One is to unplug the joystick and plug the scanner into the No. 2 USB port on the back of the machine. Since USB is plug-and-play, you can unplug the mouse and plug the joystick into that port.

More expensive, yet easier on you, is to buy a USB hub and plug it into the second USB port, then plug both the scanner and the joystick into it. I recommend the Asante Friendlynet USB hub, available at any mac internet or mail order store. I have had no problems with mine.

Hope this helps.

[mdf-occ1]

Thanks for the info. I kinda figured that the scanner was the prob, but maybe the mouse draws too much as well (it cuts out sometimes), I think I'll be looking into a Hub very soon. My scanner won't reach the back of the computer, so this is probably my best bet.

Thanks!

[Feathers]

I believe the limit for a USB bus powered device is 12watts or 2.5amps at 5volts. This is a miserable amount by any standard! A powered hub - Entrega(now Xircom) are my favourite - is an smart solution. Go right for the 7-Port. It's amazing how quick you can fill a 4-Port!