Question : Direct Cable Connection between unequal computers

I have two computers and I would like to set up a Direct Cable
connection.  However, they are not equally equipped:

Desktop Machine has -
  Serial port
  Parallel port
  USB port

Laptop Machine has -
  USB port
  Infrared port
  PCMCIA slot

There is no obvious answer (to me, at least).

Thinking about the desktop serial port, would it be possible to
somehow emulate one on the laptop? I would be prepared to buy some
gadget to connect to any of the laptop ports. The lousy speed of the
serial port is a general drawback for all soultions along this line.

Thinking about the USB port, any possibilities here? Ideally just some
kind of "null modem USB cable" and some SW to make it all play.

And the parallel port ...? I'm clueless here.

Answer : Direct Cable Connection between unequal computers

I wouldn't expect you to find somethin like USB - IrDA transceiver.
But most likely you can get an "External IrDA port", which should connect to serial the serial port and see, if that one can help you out!
Check out: www.illinoiscomputer.com/IRDA.htm