This read-only DisplayString reports the collection start time of a specific history bin in the extended Tx/Rx PM history table, per its description, marking exactly when this bin's counting period began. Because a PM instance accumulates many sequential bins over time, this timestamp is what lets an engineer place a specific bin's counter values, like the byte and packet counts covered elsewhere in this table, at a precise point on the interface's traffic timeline. An engineer investigating a traffic spike reported around a certain time would use this field to identify exactly which bin in the history table corresponds to that window before reading its associated counters.