NorthStar 951X Operator's Manual page 49

Chapter 3 - Using the Controls
Question windows appear when the unit needs to know more
Question windows
about what you want to do. A question mark always appears in
this type of window.
You must respond to any question window by pressing the
(17(5 key to answer yes, or &/($5 to answer no. All other
keys, including the function keys, are inactive when a ques-
tion window is displayed.
951/952 Operator's Manual Rev. B Page 39