Serial port using USB adaptor

Corinna Vinschen
Fri Feb 29 11:36:00 GMT 2008

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.

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.


Corinna Vinschen                  Please, send mails regarding Cygwin to
Cygwin Project Co-Leader          cygwin AT cygwin DOT com
Red Hat

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