This reports the lowest Q-factor recorded for this OTU signal during the bin, a logarithmic signal-quality/margin figure stored in the milli-scaled PmInteger32Milli format. Because this reading sits in the rolling window of completed 15-minute history bins for this OTU signal, Q-factor condenses optical SNR and receiver margin into one number, and this minimum tells an engineer how close this specific signal came to its worst-case margin during the interval, not just its typical condition. For example, a Q-factor that averages 9.5 dB on this OTU signal but dips to a minimum of 7.0 dB in the same bin shows the link occasionally operates much closer to its FEC-failure threshold, often around 5.5-6 dB, than the average suggests, within that completed 15-minute window.