NuTone Intercom Photo Gallery > Nutone Intercom IMA303 > NuTone Model IMA303 Control Switches
Behind the fold down panel you will find the room control switches along with the "volume all speakers" and tone control adjustments
The 4 tak and listen push buttons are common sources of problems on the IMA303. They wear from dirt and dust. Often cleaning and lubricating them will help. These switches are no longer avaialbe from NuTone.
Replacements can be sourced from other vendors