The graphic on p.108 of the M operation doc shows the Ring <-> Fm setting on the sub display and the FM Level and Ring Level settings on the main display for Osc 1 of an AN-X part.

The FM Level is 0 and can't be seen but the Ring Level of 66 can be seen on the sub display as 'Ring 66'.

There is only ONE knob, and value, on the sub display. Whether the value displayed is FM Level or Ring Level depends on 1) which Level you first set and 2) the relative value of FM level versus Ring Level.

Huh? The main display has TWO knobs and values - one for FM and one for Ring. But the sub display only has one knob and value.

1. Init Normal (AN-X)

2. edit part 1 Osc 1 as shown in the graphic on p.108

3. the sub display with show '0' as the value for 'Ring <-> Fm' but will NOT indicate either Ring or Fm.

4. turn the knob clockwise and you will see 'FM 1' and higher values ranging from 0-255.

5. turn the knob counterclockwise and you will see 'Ring 1' and higher values ranging from 0-255.

6. Read #4 and #5 again 

7. Values increase in one direction for FM and in the other direction for Ring.

Now the fun begins 

1. move the Ring Level knob on the main display to a value of 66

2. the sub display now shows 'Ring 66'

3. move the Fm Level knob on the main display and notice the sub display does NOT change even though the main display shows the Fm level increasing.

4. keep moving the Fm Level knob and SLOWLY go from below 66 to above 66 while you watch the sub display

5. when you pass 66 the display changes to 'FM 67', 'FM 68' up to 'FM 255'.

6. decrease the Fm Level knob and when you go from 67 to 66 the sub display will change from 'FM 67' to 'Ring 66'.

7. The sub display will never show any Ring value except 'Ring 66' no matter what value you set for FM Level using the main display knob.

8. The sub display will never show any Fm Level below 67 using the main display FM Level knob.

There seems to be a disconnect between the sub and main displays.

But WAIT! There's more.

9. Set the Fm Level to 50 using the main display knob.

10. Notice the sub display shows 'Ring 66' and the main display shows 66 for ring level and 60 for Fm level

11. Nudge the sub display 'Ring <-> Fm' knob

12. the Fm Level is instantly reset to ZERO!

13. the Ring Level gets reset to ZERO if you nudge the 'Ring <-> Fm' knob when the sub display shows 'FM 66' (or other FM value).

I don't see why either FM or Ring levels should get reset to zero if you tweak the sub display knob.