This read-write INTEGER (locked(0), usable(1)) reports and controls a line's lock state, and setting it to usable resets the password failure counter and unlocks a locked-out user on that line, with the entry only existing if the line itself exists. An admin cares because this is the direct remote remediation for a line-based lockout, distinct from the system-password-level unlock objects. For example, an admin whose remote colleague is locked out of Telnet access on a specific line would set this object to usable to both clear the failure count and restore access.