This read-write TruthValue enables or disables the port's reaction to JDSU in-band loopback and hello control frames; when disabled, the FPGA does not even filter those frames up to the processor, and disabling it while a JDSU loopback is active releases that loopback. An administrator toggles this when a field technician needs to run a JDSU test-set-based in-band loopback on a live circuit, since the port does not need to be placed into maintenance state for the loopback to work. For example, a technician would enable this object to let a JDSU test set establish a loopback for circuit turn-up testing, then disable it afterward so the port stops reacting to any further loopback frames.