Interfacing legacy serial applications with new USB devices

Discussion in 'Windows Vista Drivers' started by Scott Ballard, Oct 20, 2004.

  1. Greetings,

    I have numerous legacy applications that communicate with hardware via
    RS232. Now, the hardware is USB interface only. Do I have to write a
    device driver for the USB hardware that enumerates itself as a virtual
    serial port on the PC? Is there a 3rd party software solution that
    would help? I don't believe there's a simple hardware solution such
    as a cable that will convert the USB hardware to serial (I've seen
    cables for the other way around ... serial hardware to USB). Any
    ideas or suggestions would be much appreciated.

    Thank you in advance,

    Scott Ballard
    Scott Ballard, Oct 20, 2004
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  2. Scott Ballard

    Robby Tanner Guest

    In general, cross-posting is considered a no-no.

    If the hardware presents itself as COMx, why would you have to change
    anything other than the port the applications talk to?

    Robby Tanner, Oct 20, 2004
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  3. Scott Ballard

    Walter Oney Guest

    Yes. Furthermore, the driver is going to be specific to the USB device.
    It's unlikely that you would find a generic solution to the problem.
    Walter Oney, Oct 20, 2004
  4. Scott Ballard

    Walter Oney Guest

    Not that I ever knew.
    His point was that his device does NOT look like a COM port.
    Walter Oney, Oct 20, 2004
  5. Scott Ballard

    Robby Tanner Guest

    You've never heard people complain of cross-posting before?

    Ah yes, misread that bit.

    Robby Tanner, Oct 20, 2004
  6. Hi Rob,

    Thanks for the quick reply. The hardware doesn't present itself as
    anything as no device drivers have been written yet! I guess I just
    wanted to confirm the best way to do it before I spend time
    implementing a solution. It seems to me the best way is to write a
    device driver for the hardware so that it presents itself as COMx. I
    just wanted to make sure there's no other way than to write the device

    As for cross-posting, I usually limit myself to a maximum of three
    groups. No one's complained before so I apologize if I've violated
    any etiquette specific to this group.


    Scott Ballard
    Scott Ballard, Oct 20, 2004
  7. Scott Ballard

    Robby Tanner Guest

    I misread your first post. Since it seems that some driver will have to be
    written, having it emulate a COM port is an option.
    No worries there, it appears you haven't. The members of some other servers
    I've perused are downright militant about it. Not so here though.

    Robby Tanner, Oct 22, 2004
  8. Scott Ballard

    revo Guest

    Hi, read the post about usbser.sys on 21/09 by holi, that is about the
    same. On the atmel website, look for application note that needs file implement the cdc driver in the usb controller in
    your device. Next use the inf files used in the same application note.

    It is time saving to say the least. It will present itself as a comm port
    on windows.

    Worked for me!

    revo, Oct 22, 2004
  9. Several vendors have frameworks for Virtual Serial Port (VSP) creation
    which more or less solve the problem of writing a VSP from the ground
    up. I suggest using google keywords "Virtual Serial Port" and see
    what rises. Vendor support and robust reference designs SDK's and
    tools are critical for these implementations, and your mileage will
    vary depending upon the vendor's commitment.


    Sherman Couch
    Consulting Software Engineer
    Constellation Data Systems, Inc.
    Sherman Couch, Nov 10, 2004
  10. Scott Ballard

    Robby Tanner Guest

    You might want to look at a serial port emulation driver available from,

    I'm not sure if the driver is written as WDM (likely not), but I've
    installed and used it. Experiences may vary.

    Robby Tanner, Nov 10, 2004
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