Go to Sound control in Dev. user settings to adjust the volume levels of the MX490 Series printer.
Solution
To adjust the volume levels of the MX490 Series printers, follow the steps below.
Press the Setup button and then press the right arrow until Device settings appears. Press OK.
Press the right arrow until Dev. user settings appears. Press OK.
Press the right arrow until Sound control appears. Press OK.
In the Sound control menu, use the left and right arrow keys to choose between Keypad sound, Alarm sound, Line monitor sound, and Offhook alarm. Select the option you want and press OK.
Use the left and right arrows to toggle the sound ON or OFF. Press OK.
button and then press the right arrow 
until Device settings appears. Press OK.
and right