Controlling spindle with RS-422/RS-485?

Hello,At my university, we have acquired a portal milling machine from 1998. We are interested in installing LinuxCNC on it.In 2001, the machine received a new frequency converter, an Isel FC2200-C. We aim to control the spindle using the Mesa 7i96s board. The question now is how to accomplish this.Is it possible to control it using RS-422 or RS-485? If so, how would we go about it?Alternatively, do we need to connect via the 15-pin plug?I have attached the pin layout, but unfortunately, it's in German.
translation for the 15pin Plug:

X1:
Pin 1: reference ground analog  Pin 2:Auxiliary voltage + 10 V
Pin 3: start left Pin 4: Error acknowledgment (PLC-compatible)
Pin 5: Signal voltage (+ 24 V) Pin 6: Output A2 (max. 20 mA)
Pin 7: GND Pin 8: not occupied
Pin 9: Analog setpoint  Pin 10: Enable (PLC-compatible)
Pin 11: start right Pin 12: Pulse generator (5 V... 30 V)
Pin 13: Output A1 (max. 100 mA) pin 14: Rotational speed actual value (0 V... 5 V)
Pin 15: not occupied

thanks

Assuming analog control, the analog section looks like it should be:
X1               7I96S
2 10V --> 7I96S SPINDLE+ (TB2.24)
9 ANALOG SETPOINT --> 7I96S SPINDLE OUT (TB2.23)
1 ANALOG GROUND --> 7I96S SPINDLE- (TB2.22)

Not sure about the digital control pins, probable need an
example from the manual for that.

 

We wired the frequency converter to the 15pin plug and get it done.

thanks