I have a CS100M upgraded from an OP81, and it goes like this: There are 8 FIJI cards, in the front they have a display each numbered G0S0 tru G3S1. S is the ring and G is
<------------------------< <------------------------< the card number, so the rings are like this |->G0S0->G1S0->G2S0->G3SO-> and |->G3S1->G2S1->G1S1->G1S0->
The direction of the ring goes from the TX FO conector to the RX of the next card. at the last card the FO is connected to the RX of the 1st card, thus completing the ring. I found out this chasing the FO tru the shelves.
I hope this is useful.