But this defeats the purpose of making the software unknowledgable of what transfer medium (irda or serial cable) is being used. The the firmware it expects to receive data from the "master" aka PCPalm and respond to whatever the heck it is.

Also, the firmware will not initiate the communications so I would have no way of just flipping a switch before the other device starts transmitting.

So I take it a logic gate is the way to go in this situation.

thanks