Q:  How do I read and write to a com-port?

A:

program PortAccess;

var
  port: TextFile;
  x: char;

begin
  Assign(port, 'COM2');
  Rewrite(port);
  write(port, 'AS5', #13);
  { sample uses:
  read(port, x);
  write(port, x);
  }
  close(port);
end.