Quote from Hangar45 Admin on December 18, 2017, 8:44 am

(Original thread started on 08-01-13 by Ron Rollo)

What I am experiencing is one of those things that drives me nuts! Several months back I thought it would be cool to get two of the same type of powered USB hubs. I chose the D-Link 2.0 7 port hub. From what I understand about powered hubs is that they are pretty much just plug and play, they do all the work as far as figuring out what you have plugged into it, what port is what and keeping things separated. So easy a cave man can do it as they would say!

 

So to tell the story, I had one powered USB hub plugged into my server and the other plugged into my client. At that time, I was running all of my interface cards off of the client and had several USB items plugged into the powered USB hub going to the client computer. For the life of me, I could not get that powered USB hub to work and I ended up just running very long USB cables (25 foot long) straight to the client computer. The other identical D-Link hub was working with the server computer flawlessly just so you know.

 

As you may be aware of, the maximum length recommended for a USB cable is 16' 4", or in other words 15' because that is the longest size you can get without shopping on eBay! Anything over 16'4" and you theoretically start to loose signal strength which is why I am so hell bent on boosting the signal. But as it turns out 25 foot long cables seem to work perfectly well compared to the powered hub that does not work at all.

 

Meanwhile, the powered hub on the server computer was and is still working perfectly as designed and expected.

 

About two months ago, I moved all of the interface cards over to the server computer using the same powered USB hub that has always been working with the server. At this point, the only USB items that are plugged into the client are the mouse and keyboard which does not need a powered hub because they plug directly into the client.

 

As the project continues to grow, the need for more and more places to stick USB plugs grow too, most recently the CDR needed a place to plug into. (I also have two PoKeys56U cards). So I try to plug a second D-Link into the server computer for an additional seven ports for these three new items. I RAN INTO THE SAME PROBLEM AS BEFORE! Either the components would not be recognized or the USB would just kill over.

 

In the meantime, to get my CDR up and running and to override the problem, I grabbed my trusty 25 foot long (outlawed in some states) cable, plugged it into the server and directly into the CDR sub panel. It works. (but it shouldn't) The USB hub should work, but it don't! See why I'm going nuts?

 

So at this point I was thinking that there was something wrong with the powered USB hub that I had initially plugged into the client and now had plugged into the server as a second USB hub. So I bought another, identical D-Link powered USB hub.

 

After a few days the new hub arrives but the same problems remain. I have tried different power supplies for the USB hub and different USB lines with the same negative results which tells me that there is nothing wrong with the USB hubs, it's some sort of conflict.  Two D-Links hubs pictured below:

 

I am almost out of ideas and thoughts on this. My understanding is that you can plug as many USB hubs into a computer as you have places to plug them in. You can even plug powered USB hubs into powered USB hubs to daisy chain them if you wanted to or needed to.

 

Is this another case where having two of the same thing is confusing the computer?

Should I try a different brand of powered USB hub to work side by side with the D-Link?

 

If so, I have two perfectly working D-Link hubs for sale or trade!  Any thoughts are very welcome.

 

(Posted by Alan Norris on 08-01-13)

Try looking in Device Manager and see if the information for the two hubs are the same. They really shouldn't be as WIN is supposed to allocate IRQs, IOs and Interrupts for each device so they are not confused. Also check the Event Log for USB errors.

 

I found this on a forum:

"Identical serial numbers - the serial number in a device, if it exists, must be unique for each device that shares the same USB Vendor ID and Product ID. Occasionally hardware vendors mistakenly program devices with identical serial numbers. When two or more USB devices with identical serial numbers are plugged into the same system, only the first one plugged in functions."  So check the serial numbers.

 

(Posted by Rand Mathews on 08-01-13)

Have you tried plugging in your USB peripherals one at a time and testing that each one works, then add the next one and so on? I have a cheap 10 port hub I got off eBay and another 4 port non powered adapter I got at Radio shack, and that one plugs into the 10 port one. Sometimes the things get confused or something and it will lose a port, then I either have to unplug the device and plug it back in, listen for the windows audio glitch and it will start working.

 

Other times I either have to unplug the entire hub, or just reboot the computer. When you have that many USB's they seem to freak out sometimes. I'm sure you've tried the one at a time method, but make sure you don't have a bad cable or device that is throwing the whole thing off.

 

(Posted by Ron Rollo on 08-01-13)

Thanks guys for the suggestions. The one thing I am confident about is that the USB hubs, cables and power supplies are all working fine. I do highly suspect that it is an issue of two devices of the same make attempting to share the same name.

 

Remember I had a very similar incident where I had two identical Leo Bondar BU0836X cards. I tried everything before I finally gave up and replaced one with a Leo Bodnar BU0836A card. The issue was solved. I hope this is the case here.

 

Rand, I hate that you have also been through your share of USB hub issues, but at least I know it is somewhat expected.

 

(Posted by Alan Norris on 08-02-13)

Same make and model shouldn't be a problem as Windows looks for the hard coded serial number.

 

(Posted by Ron Rollo on 08-02-13)

Hey Alan, your right, "Shouldn't"......and that is what is so frustrating about this issue!  I'm going to get another make and model powered USB to see if that solves the issue. I have three D-Link powered hubs. Two of them have the same P/N. All three have different S/N.

 

UPDATE:

So I purchased a 7 port Ultra powered hub. I have three cards plugged into it and so far, it seems to work, although the two PoKeys are not running anything yet. I did get a failure stating that one of my powered hubs had to shut down due to a power spike.

 

All in all, running two different powered hubs is working and I have much better results!

Problem solved!