33120A UNLOCKED Message on POST?

Frequently Asked Questions (FAQs)SummaryOption 001 for the 33120A displays the UNLOCKED flag during power on.QuestionWhy does the option 001 33120A display "UNLOCKED" when turned on?AnswerThe 33120A temporarily displays the "UNLOCKED" message during a self-test, when the 33120A is powered up and it is unable to detect an external 10MHz TTL signal. The 33120A also displays this message when removing the reference signal and while the 33120A is in a phase lock operation. The 33120A temporarily displays the message "LOCKED" when it detects a reference signal.