mode com2:48,8,n,2,b should be the command you're looking for, I think... Then you can copy a file to the port containing your commands.
Find a full copy of DOS 6.22 and copy the QBASIC*.* and HELP*.* files to your Win9x c:\windows\command directory, and you'll have a nice reference to DOS commands, most of which work the same between DOS 6.22 and DOS 7.