National Instruments provides a VISA library on the Macintosh and I
recommend you use that.
VISA calls on the Mac let you communicate over GPIB, Serial, and VXI if you
You can download NI-VISA from ftp.ni.com/support/visa/drivers
Senior Software Engineer, VISA
"Xia Hong" wrote in message
> I use C code to talk to my GPIB card. I now want to include in the same C
> a section that talks to my RS422 port (on a Macintosh). In other words,
> want to write one C program which talks to both my GPIB card and a Mac
> RS422 port. Where do I find a driver file which allows C to talk to a Mac
> RS422 port?