Absolute rotary Encoder SSI SPI how ?

Hello,

I like to read Data from "OCD-S101G-1212-C100-PRL".

My connection are:
A and B to D+ and D-
R to receive in arduino input
Y and Z to clock+ and clock-
D as arduino output to generate clock

And my Chip is a:
SN75179BD RS422, RS485

Can Somebody help me with code?

Thank you
Schnibli