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 playerAM/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. Remote emergency paging capabilities 20-watt intercom; separate 35-watt program channel Provision for time signalling, telco and voice call-in Aural and visual monitoring of program material, as well as level controls Transmit a time tone for classroom change, etc. Emergency All-Call with a single push-button Emergency announcements take precedence over all system functions and are transmitted at a predetermined level Emergency paging from a remote telephone or microphone Teachers converse hands-free with the control center operator over their individual classroom speaker Calls to staff locations are announced by a supervisory tone signal, which repeats at regular intervals to indicate that the channel is open and the room is being monitored Classrooms can be equipped with call-in switches to call the control center, with options for privacy to voice call-in A CD player-AM/FM receiver can be installed when system capacity does not exceed 50 stations Sturdy desktop cabinet finished in an attractive simulated wood grain finish