It seems to me that the most interesting pins are FAL/FAH and PTAL/PTAH. From what I understand they are the actual amplified/ filtered signal feeded to KL4X.
What are outputs of FAL/FAH and PTAL/PTAH?
Is it safe to connect arduino analog in to the pins (14,16,18,26) of KL4X and read the values (seems to be 0-4v)?
I would also like to know what pins FREQ1, FREQ2 and AZCNT are.