Hi guys, been getting this issue for a while now on this Schindler Mxgc.

What would happen is the aux or slave COP panel would not respond to calls, but the master COP would.

This happens randomly and will come and go.

There is also security installed on this lift. (Security swipe)

The only fault I can see on the system is;
ERROR LON
1209 MISSING NODE
0x000c000f

Any ideas where I can start looking?

I have provided a link with 4 photos of the setup.
http://imgur.com/a/LNIVo

Any help would be appreciated!
I can provide any more pictures and info if needed. And yes I am a licensed electrician and elevator engineer.
(I am from Australia so I pardon of some of the words I used sound different than the normal terms)