bitsPortTransmitQL is a read-only value reporting the quality level currently being transmitted out of this BITS port, which is not meaningful if the port's QL mode is disabled. An administrator monitors this to confirm the device is advertising the correct synchronization quality to whatever downstream equipment is fed by this BITS-OUT port. For example, if this NE has selected a degraded internal oscillator as its timing source, the transmitted QL on its BITS-OUT port should reflect that lower quality so downstream devices can decide not to prefer it.