Speaker Station or Headset Station Use the built-in speaker for listening and add an optional MCP-90 series Gooseneck Panel Microphone for talkback. You can also turn off the speaker volume, and plug in headsets for private communication.Voice Activated Microphone (VOX) Separate controls adjust the voice activation level for the headset microphone and panel microphone inputs.Public Address (PA) Output, with PA key Use your intercom microphone to talk over a PA system.Back-lit Keys Improves visibility in low-light Incoming Call IndicationsRed flashing call light, with beep tone if desired.Instantaneous Auto-Reset Instantaneous Auto Reset (IAR), the newest technology in performance and safety, which uses a revolutionary new circuitry that dynamically monitors line fault conditions. Then, when the fault is removed, automatically brings individual power supply channels up.Mic Kill Key You can turn off all microphones on a channel to quickly clear the channel.Program Input for Each Channel Connect any line-level audio source for monitoring in the speaker or headset, or for routing to the intercom channel. The program audio to the channel can be set to interrupt while the MS-2002 operator is talking on the channel.Binaural (Stereo) Listening with External Powered Speakers You can connect external powered speakers and then monitor channel 1 and 2 as separate right and left audio.Expandable Add more channels by connecting optional EMS-4001 Expansion Stations. Each EMS-4001 adds four additional powered channels (up to eighteen channels).Clear-Com Compatible.