You can change the sound if required in the SETTINGS of the customer panel profile in RSC+ App.
> Log in to RSC+ App
>Select the panel profile
>Touch on SETTINGS
You will see the notification sound (default Beep Once)
>Touch on this setting and you should see a listing of available notification sounds in your phone to select from.
Select notification sound and SAVE
Keep in mind , if you select a long sound file, ( a ringing tone) it will continue until you actually look at the message on your phone.
*Note: Currently iOS devices do not allow you to change the notification sounds, this is currently due to app restriction within the iOS platform.