Serial port using USB adaptor

Fri Feb 29 13:06:00 GMT 2008

On 2/29/08, Corinna Vinschen <> wrote:
> On Feb 29 12:43, hce wrote:
>  > Hi,
>  >
>  > I  have a linux serial port problem compiled by Cygwin on window, it
>  > runs fine if it connects a 9-pin serial cable and the device name is
>  > /dev/ttyS0 (it does not work with com1, I have to translate it to
>  > /dev/ttyS0). The problem is when I run the program in a PC without a
>  > physical 9-pin serial port on hardware:
>  >
>  > (1) If there is no USB Serial adaptor connected, it still opens
>  > /dev/ttyS0 without any errors. Then, it sends data to that port, and
>  > timeout (does not work).
>  >
>  > (2) If I plug a USB-Serial adaptor and change the device name to
>  > /dev/ttyUSB0, it opens that port witout problem but cannot connect to
>  > the serial device.
> /dev/ttyUSB0 works?!?  It's no device name recognized by Cygwin, so
>  I assume you created a file on the disk called /dev/ttyUSB0 when
>  using it.

It was copied from Linux.

>  My knowledge about serial I/O is rather clumsy, but isn't there a
>  virtual COM port attached, or can't you attach a virtual COM port to
>  your USB I/O?  AFAIK, you should find something like, say, COM9, which
>  would be available as /dev/com9 or /dev/ttyS8.

My knowledge to Window machine is also limited. So, I should open
/dev/com9 or /dev/ttyS8 regardless it is connected to a serial cable
or a USB serial adaptor. I don't have the Window machine at home, I'll
try next day.

Thank you Corinna.


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