I am facing problem in communicating to GE Fanuk System

Hi All,
We are using S7 414H Redundant in our material handling plant which is under a GE Fanuk Redundant System.
I am facing problem in communicating to GE Fanuk System.
Both should communicate as Master so that we can fetch and write data to and fro.
Do we need DP-DP couplers or communication can be done without it???

GE Fanuk system is using cards IC693PBS201 as Profibus Communication cards for communication with us and are using CPU :IC693CPU360.

How can we communicate??Any suggestion will be helpful.

Regards,
JD

Splitted from GE FANUC rx3i to S7 317 profibus communication.