Resetting a USB port via software.

tomstickland

We have a problem at work where noise/static on a USB line causes it to disconnect every now and again. The software we've developed just opens up a dialogue box and tells the user to unplug the item and plug it back in. It's a bit of a faff though and I'd like to replace it with an automatic reconnect.

One guy spent some time searching round the net for a solution and couldn't find anything. However, the other day, someone told me that you can get windows to reset the USB connections.

So the question is, does anyone know how to get windows to reset the USB connections?

MoneyTown

Not sure how to do this in software but have you tried shielding the USB device and its cable from interference ?

tomstickland

Yes, we've done a fair bit of work with anti-static spray and using cables with the inductor chokes on them.

I've been told that a possible problem is that we have motor control cards on the PCI slots and these are known to generate noise.

MoneyTown

I guess you could use a different set of USB inputs as a test.

Something like: http://www.ebuyer.com/product/108594

To back up that idea I've just seen this discussion:
http://line6.com/support/entry.jspa?externalID=4282

Belnahua

Is it possible to put a powered USB hub in between the devices and use 2 shorter cables?

mdbarber

don't see any reason why it can't be done, pretty sure that's what happens during the PnP routine anyway, have a look at the rundll options available especially for printing what type of device are you using on the line?

CHR15

Just thinking aloud but how about removing the usb from Device manager and doing a Scan for hardware changes?

tomstickland

A PCI USB card looks like it's worth a try. I'll see if there are any spare PCI slots.

I'd still like to dig down to what I could do in software. When the computer switches on it must scan the USB ports for devices via some software.

rundll

So I'll do around and see what this might give.

how about removing the usb from Device manager and doing a Scan for hardware changes?

Can you expand on this a bit?

CHR15

Not sure if it would work, never tried, but go in Device Manager

Expand USB Controllers

Right click on the USB hub/controller

Chose Uninstall

Then Right click again and chose "Scan for hardware changes"

Only a couple of mouse clicks

It may well immediately find it.

buglawton

Scan for hardware changes (without de- or re-installing anything) has worked for me in the past

mdbarber

Tom can you expand on the hardware involved because it's funny but i may have had a similar issue recently.
I have a hauppauge tv card in my htpc and occasionally the remote control is crashing out, the software i am using (media portal) of which there are 2 versions so i am now trying the second and the fault is minimised.
In this instance the remote is connected/controlled via a usb chip on the tv card and it actually has a small utility to "restart" the remote, presumably sending a reset signal to the cards own usb controller
The last time this occurred i used the utility but it had no effect, only thing that worked was a total power down, i have been thru many options of OS vs driver packages but as this machine is in everyday use and the fault occurs intermittently it is a slow process to track it down.