As a prep for the PRC length measurements, I hooked up a DAC cable of LSC, CAB_H1_ISC_421, to the Dsub breakout board D1201450 at the 18th floor of the ISC rack R4 as specified in E1200408-v14. It is connected to the right half of the breakout unit.

Then I connected a TNC cable from the 2nd output port of the breakout board to the A excitation of the IMC servo board. This is a temporary configuration and allows us to remotely excite the IMC length using the LSC_EXTRA_AO_2 signal (see T1100242-v11 for the signal assignment).