Ok, from what I can see so far, the Level output runs to an LM258 Op-Amp and then to one of the Analog inputs on the onboard PIC16C73...



UPDATE: I do see something that looks like it mirrors the level output on one of the empeg pins. (shaking head) Need to trace further. But because there is only 7 pins in use (one socket is empty) that makes:

So that leaves:

PWR, GND
TX, RX
FM-MPX
AM-Audio
Level (AM/FM)

So now where does RDS fit in?

-Ben