There is a fair amount of legacy code associated with the PI code. In the distant past, only selected front-ends were able to communicate over the long range network between corner and end stations. This required channel forwarding code in the PEMEX, PEMEY and OMC models to route the PI compensation network.

Today's upgrade will eliminate the channel forwarding. So, the PI code in OMC moved to the OMCPI model, the PI code in PEMEX/Y will move to the SUSETMXPI/SUSETMYPI models, respectively. Furthermore, the channel forwarding was done using a multiplexer, where 8 2kHz channels were transported through 1 16kHz channel. This is preserved, but the multiplexer code needed to be updated to recognize that the PI models now run at 64kHz rather than the previous 16kHz.

This is in preparation of moving the OMCPI model to the new segregated OMC front-end.