The SI35A provides fast, reliable, and efficient intercommunication and tone signalling in small to medium-sized schools. The SI35A provides a 20-watt intercom amplifier to permit instant intercommunication with any speaker-equipped location, and a separate 35-watt program amplifier for simultaneous distribution of program material to other rooms or locations. The system also features an emergency page capability for emergency announcements to all stations at once.The SI35A provides complete facilities for distributing a variety of program materials from optional equipment such as microphones, CD player-AM/FM receiver, or other background music source. Selection of program material, as well as its distribution to selected rooms is accomplished with simple push-button program selection and by following the color-coded guidelines.