Here is an extract from the QBasic help (sorry if the foruatting gets messed up):
INP returns a byte read from a hardware I/O port.
OUT sends a byte to a hardware I/O port.
INP(port%)
OUT port%, data%
■ port% A number in the range 0 through 65,535 that identifies
the port.
■ data% A numeric expression in the range 0 through 255 to send
to the port.
Example:
x% = INP(&H3FC) 'Read COM1 Modem Control Register.
OUT &H3FC, (x% XOR 1) 'Change Data Terminal Ready bit.
I think that the command that you want is "pset", which appears to work just like "plot" in most BASICS.
Out of interest, why QBasic? I've never liked it (or AmigaBasic for that matter) :-)
