The first group of buttons is for selecting which key is to be used. Only one is selected at a time. The second group is used to select which, if any, of the control, alt or shift keys are to be used in combination with the first key.
The original default is shift-F12.
When the dialog box first appears, your current setting is shown.
Click on OK to apply any changes to the current session.
Click on Cancel to dismiss the dialog box without making any changes.
Note:
The selections you make in this dialog box apply only to the current
DOS session. Use Merge Setup to change your
configuration and save the changes for future use.