This is the timestamp of when the OLT's auto-discovery process first detected this ONU on the fiber, giving an install-date audit trail distinct from any later formal provisioning timestamp. It's useful for reconciling a technician's reported install time against what the network actually observed. For example, a value of '2026-08-05 09:14:22' tells the admin exactly when the fiber tech's new drop first lit up on the PON, regardless of when it was later formally accepted.