This is an old revision of the document!
by Richard Russell, February 2010
Since version 5.91a, BBC BASIC for Windows has fully supported serial ports above COM9; to open such a port you need only use the regular OPENUP function:
port% = OPENUP("COM15: baud=9600 parity=N data=8 stop=1 dtr=on rts=on")
Naturally you should specify the port parameters as required by your program.