The Bogen Multicom 2000 is the commonly used in TDSB schools for the PA system and phone intercom system. Over the years, I have experimented and found out a bit about how it works.
Audio programs are how you can send audio from a auxiliary input to the speakers throughout the school. It can be added to individual speakers, or to combined zones.
A layout of the audio program menu is as follows:
At L'Am, we had a pre-amplifier/mixer in the office PA rack, that allowed us to send multiple devices through the same program input such as the microphones, Radio L'Am, CD Player, AUX cord, etc.
We had to run through setting it so the output of the preamp would be sent through the school every time it got deactivated.
To connect everything, we had the preamp hooked up to Program 2. Zone 1 was all speakers in the school (excludes outdoor and adult ESL speakers) that we used.
See Connect Radio L'Am To Classrooms for detaiils on this.