Question: Serial Comm port in handshaking mode. What is FSX line supposed to be doing in hand shaking mode?

Answer: On the transmit side: CLKX is a continuos clocking cycle. (h1 * 2.6 for external rate, h1 * 2 for internal) FSX sends an active signal to the receiver (telling the receiver it is transmitting a word by bringing the receiver's FSR active). DX is the data line the word is transmitted across. (word is Proceeded by a 1 before the word is transmitted) on the receive side: CLKR is the clock receive for synchronization. FSR receives the 1 from the transmitter so it knows the a word is about to start. DR is where it receives the word (after the full word is received the receiver's DX transmits a 0 back)