fpc/docs/go32ex/outport.pas

{ example for : outport*()
                I/O access
}

{ This example demonstrates the use of the outport functions.

  It simply turns the PC's internal speaker on for 50 ms and off again.
}
uses crt,
     go32;

begin
     { turn on speaker }
     outportb($61, $ff);
     { wait a little bit }
     delay(50);
     { turn it off again }
     outportb($61, $0);
end.