In message <c6q432$iir$1@serpens.de>, Michael van Elst writes:
>seebs@plethora.net (Peter Seebach) writes:
>
>>I have an IR port.  It shows up as a COM port, which appears to mean that
>>it should magically "just work" as a serial port.
>
>>However, I never get anything at all from it except 0xff's, no matter what
>>baud rates are in use.
>
>IR ports often come as an IrDA high speed port with a COM 'legacy' part.
>If you use the 'legacy' part you may need to disable the high speed port
>in the BIOS.

Thanks to help from Steven M. Bellovin, I've made progress!  It turns out
that the legacy part doesn't really provide a tty-style COM port, but rather,
a thing to which "irdaattach" can attach.

With this, I've had partial success.  Once, I was able to get connected to
the port and do AT/OK sequences.  This involved using irdaattach to connect
an irframe device to /dev/tty01, and then using ircomm (from
pkgsrc/comms/birda) to attach that irframe device to /dev/ptypz.  That mostly
worked.  Mostly.  I could get PPP to start, but once it was started, it got
weird bogus data back instead of real LCP config packets; I have no idea why.

However, since the couple of times it worked, it's been impossible to make it
work.  I alternate between ircomm claiming there's no device in range, and
ircomm seeming to work, but getting I/O errors trying to open the pty it
creates.  Argh.  Maybe I'll get it debugged further on the road.  :)

-s