C250 - Changing Audio Volume
You will need the ADMIN Card to log into the menus
Press the M/ button (a padlock will display) swipe the Admin card
Select the SYSTEM icon and press the OK button
Select the SYSTEM icon and press the OK button
Use the arrow keys and navigate to the VOL option. In here you can set the volume to LOW, MID or HIGH
When you have set the volume you need press the ESC key and save the changes
Finally press the ESC key a few times to exit the menus.