The scope reading the ring fibers is currently ER/DG/RAC.06-OSC.01.  It is on channel 18 of the Diag delay generator. This channel is labelled "spare camera". I has been added it to diag_delays (will be available after the next git pull).

It was set to -49us with a scope horizontal latency of +42.5us. We changed this to set the chanel delay at -9us with a scope latency of 2.5us. So this should be transparent for all.