bitsPortSquelchQL is a read-write setting, meaningful only when QL mode is enabled, that defines the quality-level threshold below which the BITS-OUT port's output signal is squelched (suppressed) rather than transmitted. An administrator uses this to prevent a BITS-OUT port from feeding a known-bad or low-quality clock downstream once the system's own synchronization quality has degraded past an acceptable point. For example, setting the squelch QL such that the port mutes its output whenever the system falls back to a holdover or free-run quality level protects downstream equipment from locking onto an unreliable reference.