The Perpetrating PC...

  • MB:MSI Z77A-GD65
  • OS:Windows 7 Pro
  • CPU:Intel Core i5-3570k Ivy Bridge
  • Memory:16gig G.Skill Ripjaw
  • PSU:Cooler Master Silent Pro 700w
  • HD:1TB WD Cavier black
  • Rosewill rc-300e PCI Express x1 serial card
  • VGA:(2) Nvidia Quadro FX 3500 SLI
  • Monitor:24" Samsung

This computer is used to send G-Code programs to a Horizontal CNC Milling machine through serial DNC. Up until last week everything was working fine with the Rosewill serial card in the above machine. All of a sudden on Friday of last week all communications between the Horizontal CNC and the computer stopped. I asked the user if any updates had come down or new software was installed. The user assured me that nothing changed between the last time it worked and it's failure.


  1. Tried reinstalling the drivers (both with and without removing the driver first).
  2. Tried both the drivers on the CD that came with the Rosewill rc-300e card and the latest drivers online.
  3. Tried 3 different Rosewill rc-300e cards in all 5 PCIe slots (x1 and x16) on my MSI board.
  4. Tried reinstalling the OS on the PC.
  5. Tried 2 different Windows 7 computers both with Asrock Extreme 4 z77 motherboards and the Rosewill rc-300e serial cards. Neither worked.
  6. Tried connecting a different serial device (an engraving machine) to all 3 above computers (2 Asrock and 1 MSi) with the Rosewill rc-300e serial cards and all three worked fine. So it's not the ASrock or MSI PCs.
  7. I tried connecting the Horizontal to two old Windows XP Lenovo Thinkcenters with on-board serial. Those both worked fine talking to the Horizontal. So it's not the horizontal or its serial cable.
  8. So lastly I thought I'd try the Rosewill serial card in the Thinkcenter. That worked fine. So it's not the serial card.

Steps 6, 7 and 8 are what makes this whole thing weird. The only commonality that I can find is that it works with Windows XP but does not with Windows 7. BUT, it worked fine with Windows 7 prior to last Friday and absolutely nothing had changed on the PC (or any of the other Windows 7 PCs for that matter.)

Anyone have any ideas?

  • A Windows update, perhaps? You could take a look at the update history and even uninstall any recent ones though Remove Programs. It could also be another apparently unrelated program updating. – Bob Dec 27 '12 at 20:41
  • We've looked into that. The last approved updates from WSUS were 12/15. The problem started between 12/20 and 12/21. The user is adamant about nothing changing. I even gave him the "come on now, you won't get in trouble" look. He's pretty honest when it comes to that type of information, so I am pretty sure nothing software changed. The computer only has 1 piece of software that autoupdates beside the OS anyway; Adobe Reader. But still, after a full format and reinstall of the computer it doesn't work. – Albion Dec 27 '12 at 20:48
  • probably a longshot, but are the IRQ's fine? – Lorenzo Von Matterhorn Dec 31 '12 at 21:11
  • 1
    @Albion any update on your problem? – Lorenzo Von Matterhorn Jan 10 '13 at 23:31

You can always use USB-to-Serial adapter instead of the PCI-E card. Pick one based on a solid chipset from FTDI or Prolific and you will get pretty stable solution.


This may help you: open control panel and go to device manager and sees if the device is listed in windows 7 if it is click on it and it should pop up "this device is working properly or this device cannot start(error code here). Hope this helps.

  • 1
    How does that answer the question with a resolution? What if it shows "this device is working" but in fact, the issue persists? – Carl B Mar 8 '13 at 2:51

I have to apologize for not answering sooner. The problem was a bug in the licensing portion of the DNC software (MultiDNC) we were using. The manufacturer offered an update and everything started working again.

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