Jumper settings, Ohm line termination, Level adjustments – GAI-Tronics 10959-908 Rack-Mount Audio Messenger Interfaces User Manual
Page 14: Display brightness, Telephone line levels, Party line levels (model 10959-908 only), Date and time set up, Date set up
                                    Advertising
                    
                        
                    
                            
                            
            
            
                            
            
        