This selects which inband line-loopback signaling convention, CSU-style or NI-style, this DS1 port uses both when sending loop-up commands to the far end and when recognizing loop-up commands sent to it. Because different carrier equipment and network interface types expect different inband code sequences, mismatching this setting on this specific port would mean the port either fails to loop far-end equipment that expects a different convention, or fails to respond correctly when it itself is commanded into loopback by that equipment. A circuit terminating on network-interface demarcation equipment rather than a customer CSU would need pportds1InbandLoopType set to ds1NI on this port to match the loop-up codes that equipment actually recognizes.