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Main => Main Forum => Topic started by: Brax on July 11, 2003, 05:05:00 pm

Title: USB Hub Question
Post by: Brax on July 11, 2003, 05:05:00 pm
When do you require a powered hub? I plan on running an IPAC, an OptiPAC, and a Dual Strike through one. Does it need to be powered?
Title: Re:USB Hub Question
Post by: meta87 on July 11, 2003, 05:07:33 pm
My hub worked fine with 2 gamepads but when I added a third it needed the power.

Sounds like you may need to power it. :)
Title: Re:USB Hub Question
Post by: AlanS17 on July 11, 2003, 05:19:30 pm
They say that powered hubs can even perform better than direct USB connections. You're probably going to need a powered hub. They're not expensive, though. Don't get one at Best Buy. Get on at CompUSA or somewhere like that. Or even Walmart...

For small ticket items you might as well buy local. Shipping costs aren't worth it.
Title: Re:USB Hub Question
Post by: Brax on July 11, 2003, 06:11:45 pm
Why the hell do they make a 4 port non-powered hub if it won't support 4 devices!?!?!?!?!?!?!?
Title: Re:USB Hub Question
Post by: RedSquirrel on July 11, 2003, 06:54:55 pm
Why the hell do they make a 4 port non-powered hub if it won't support 4 devices!?!?!?!?!?!?!?

I have a 4 port hub, and all my devices are working A-OK. Maybe its just better power consumption? Hmm I dunno. Plus I actually have 2 x 4 port hub and everything work fine.
Title: Re:USB Hub Question
Post by: AlanS17 on July 11, 2003, 07:17:20 pm
Different devices require different amounts of power. Plus how many people use all 4 at once?

My question is why do they make a 4-port laptop USB hub. Wouldn't having all those devices defeat the purpose of being mobile?
Title: Re:USB Hub Question
Post by: grafixmonkey on July 12, 2003, 03:27:43 pm
USB ports are supposed to be able to supply like 500 mA or something (not sure if that's exactly the number but there's a standard limit) but if you have a hub that's not powered, all four devices draw from one port that can supply a max. of 500 mA.  So if you have gamepads with vibration feedback, those probably draw a good deal of power...   if they draw 200 mA each, then you can plug in two for 400 mA total, but plugging the third would be 600 mA and the port can't supply that.  Just a bank of 4 or 5 bright LEDs would bring you close to or above the 100 mA mark, so it's pretty easy to break the 500 mA limit with four devices.

If you power the hub, then each port on the hub can supply 500 mA again.


Looked at my hardware - my Microsoft optical mouse has '100 mA' marked on it.  Same with my keyboard.  My graphics tablet says 40mA, an old Logitech joystick (analog) says 25mA.  So I could plug all four of those in with no problems.   74XX chips and lots of off-the-shelf logic components (like the IPAC has on it) often draw more power than optimized commercial products.
Title: Re:USB Hub Question
Post by: Brax on July 12, 2003, 08:32:48 pm
Hmmm, the Dual Strike os only 20ma..... in wonder if the IPac and OptiPAC would take me over the limit? I wonder what 1UP has. Powered or non-powered? He has the same stuff hooked up AFAIK.
Title: Re:USB Hub Question
Post by: u_rebelscum on July 13, 2003, 05:02:30 am
Hmmm, the Dual Strike os only 20ma..... in wonder if the IPac and OptiPAC would take me over the limit? I wonder what 1UP has. Powered or non-powered? He has the same stuff hooked up AFAIK.

The amount of power needed by the optipac depends on the power needed by the trackballs and spinners attached to it.  Happ TBs are said to need quite a bit of power.  

FWIW, I can run a optipac with two trackballs (one a happs) off my computer port fine.  However I usually hook them through a powered hub since I have too many USB stuff, and try to give them all enough power.  

You see, my (former) boss broke one computer USB port and a digital camera hooked up to it when he tried to download images without enough power. :o  The manual even said don't try to run it straight off the computer port because of the lack of power, but did that stop him?  Nope.  (The camera was repaired, and he only lost the memory card in the camera + the port.)
Title: Re:USB Hub Question
Post by: grafixmonkey on July 15, 2003, 03:05:13 am
burned out a port and a camera?  that sucks!  I thought those things had some kinda protection on them...   guess not.

I just remembered, the USB hub itself contains logic.  So the hub itself will consume some power.  (so 490 mA of stuff might still not work if it doesn't have a power supply to itself.)

Oh yeah and I think usb hubs, or at least good ones, have "protected" ports, so if something like that happens or you accidentally cross something on your ipac, you'd probably just kill the usb hub's port and not something on your computer's motherboard.  Might be worth it to all the tinkerers out there.

Title: Re:USB Hub Question
Post by: Spaced Invader on July 15, 2003, 03:29:44 am
Not all USB ports are up to spec. I had a machine that wouldn't even power a 200mA LAN interface without a powered hub. With the hub I could run a  toaster from the thing. Well, maybe not a toaster...but point is, a powered hub is worth the couple extra dollars you'll  pay. And you'll be covered if you want to plug something else in later. But what do I know?
Title: Re:USB Hub Question
Post by: IceCold on July 15, 2003, 05:05:37 pm
The only time I've had any trouble with having a non powered 4 port hub is when I had a webcam hooked up to one of the ports.

I would think you should be fine, but I don't know.
Title: Re:USB Hub Question
Post by: night on July 15, 2003, 07:38:32 pm
if yall have XP, you know u can go into the USB Root Hub in device manager, the power tab, and it will tell you how much power each device uses.
my mouse is 50ma, joystick is 100, and my wacom tablet is 500ma :o