NARDA 8718B - Manual (Page 81)

80 Operating the Meter
Display Blanking and Keypad Lockout
To both blank the display and lock the keypad...
1. Access the menu system by pressing the function key
that corresponds to the legend below MENU on the
bottom line of the display.
2. Press number 8 (NEXT) to select the Second Menu
Screen.
3. Press 7 to select BLANK.
4. The meter will automatically return to the
measurements mode but will be blank. The keypad
will also be locked. Only the Off key will respond to
commands individually.
To both activate the display and unlock the keypad...
5. Simultaneously depress both the Enter and Esc keys
to both activate the display and unlock the keypad.
These are the two dark blue keys.