Need Keyspan USB serial adapter to appear as COM1

Question

Need Keyspan USB serial adapter to appear as COM1

I have a Windows application (Garmin MapSource) that needs to connect to my GPS device via a serial port. For the serial port, I have a Keyspan USB-to-serial adapter (USA-19). I had this working on my old QuickSilver using VPC 6 and Panther. Specifically, the program would think that the USB serial port was connected to COM1.

However, I've upgraded to VPC 7 on an iMac with Tiger. VPC 7 sees the USB adapter, but I cannot associate it with COM1. The Windows program sees an empty COM1.

Does anybody know how to make the USB-to-serial adapter appear as COM1?

Jeff

Posted on Sep 2, 2005 4:11 PM

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Answer 1

Sep 4, 2005 2:52 AM in response to William Davis

Thank you, that was a great help. I'm able to assign the Keyspan to COM3, but when I use the Keyspan driver to test the port, the test fails with the error "unable to open port." (And the application cannot open COM3, either.) In the VPC settings, the Keyspan is seen attached to the USB port, and the Keyspan driver recognizes that the device is connected.

Do you have any idea why the adapter is recognized as being connected to the USB, but the driver cannot open the port?

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Answer 2

asrai

Level 1

133 points

Nov 8, 2005 6:55 AM in response to asrai

Well it looks like version 2.0 from Keyspan doesn't fix this... I spoke with them and they passed the buck to MS and said it's a VPC issue. LOL, it must be nice to never have to take responsibility for anything...

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Answer 3

Sep 2, 2005 8:04 PM in response to Jeffrey Mattox

On Windows, Com1 is reserved for a physical serial port. If one isn't present, you can't make a device (a modem for instance) occupy Com1.

The reason for this is that most PCI busmasters address Com1 at the BIOS to allow a physical port to be attached directly to the southbridge chip - This provisioning still exists even if the logic board to which the southbridge is attached has no physical link to those pins.

Why this matters in your case: VPC7 does a "better" job of emulating actual PCI bus conditions of a Windows PC because the VPC is emulating newer PCI busmastering hardware. This makes certain expectations of software more likely to be true, and allows the VPC to actually use more of the Mac hardware out there (because new macs use PCI busmastering that is extremely similar to non-macs.) Your best bet is to attempt to assign the adapter to Com3 and try to convince the Garmin app that your device is located on Com3.

You may also need to reinstall the Windows driver for the USB adapter and see if there's an option in the installer for it to hijack Com1 (something some IR serial port devices did when IR was fairly new)

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Answer 4

Sep 11, 2005 5:33 PM in response to Jeffrey Mattox

It still doesn't work, but after doing more research, I learned this: Load the Keyspan driver (1.8 is the latest so far) under Mac OS (not Windows). This way, the Keyspan adapter shows up in the list of modems under COM1. I can select that as COM1, but I'm still unable to get data in or out. Using Google, I see that many other people are having this problem, but there's no consensus about whether the problem is Apple's or Keyspan's.

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Answer 5

asrai

Level 1

133 points

Sep 20, 2005 9:23 AM in response to Jeffrey Mattox

Same problem here. Things were working fine with COM1 set to the Keyspan, now for some reason it's not communicating anymore. The Keyspan assistant in Windows doesn't see the USA19W anymore either, however it shows up fine in OSX. Anyone have any ideas?

--
Chris

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