This selects which type of far-end equipment, an OCU, DSU, or CSU, the loop-up code sent from this port is designed to address for DS0 far-end testing. Different equipment types respond to different inband loop-up signaling sequences, so telling this port which type it is addressing on this specific channel is what determines which actual signaling sequence gets sent to reach and loop that equipment. If the far end of this DS0 channel terminates on a CSU rather than a DSU, setting pportDS0FarendLpbkType to CSU (3) ensures the correct loop-up sequence is used instead of one the CSU would not recognize.