Interacoustics AS608 Operation Manual page 22

Press Change to access the license key of the AS608/AS608e
instrument.
Press Change to enter and/or modify the license key of the
AS608/AS608e instrument.
Use button 2 to change the letter and button 1 to move the
cursor
Press Save to return to the main setup menu.
About
Press Change to access the information in the About section.
Press Back to return to the main setup menu.
Press Save to return to measurement screen of the AS608/AS608e.
AS608/AS608e Operation Manual Page18