I've modified the Dexter program a little bit so that the transmit buffer gets emptied using interrupts rather than polling to see when it's time to send another byte. This should have the effect of faster transmit speed. It also may throw off critical timing so I will have to do some tests and may have to disable it if it is a problem.
I also started hooking up the MODE button to make the LDP choice cycle when you press it. This is not finished yet.