IBM 5280 User's Setup Manual page 110

2. If you have a Keylock feature, turn the keylock to the right
(clockwise).
The keylock is a feature that may be on IBM
m~chines
5285, 5286, or 5288.
Two keys are shipped with each machine that has the Keylock feature. You
will find these keys in the envelope in which you found this manual. Use the
key that permits you to turn the lock to the right.
Locked
Position
3. Locate the verification diskette.
The verification diskette will be found in the envelope in which you found
this manual. Take the diskette out of the protective envelope.
User's Setup Procedures 103