1) IC-29 Intercom Amplifier
1) IS-3022BB Speaker Station
1) IS-3100 Vandal-Resistant Speaker Station

This setup is used most often in vandal-resistant applications, or where separate microphones cannot be installed because of wiring or space restrictions. This system is Push-To-Talk from the inside, with Return-To-Listen to the outside. A call button on the IS-3100 turns on the amplifier and alerts the inside with a call tone.

NOTE: Complete setup information including internal jumper settings and detailed wiring is available for download in PDF form.  IC-29 Intercom Amplifier - Typical Spkr-Spkr Setup