Features

Master intercom works with any combination of up to three door, sub-master, or master intercoms (sold separately) to enable audio communication with visitors and other rooms within the building
Three buttons with LED indicators allow the master intercom operator to direct a call and communicate with the desired door or sub-master intercom
Privacy button prevents other intercom users in the system from overhearing a conversation with another intercom
Listening feature allows the master intercom operator to receive audio transmission from a door or sub-master intercom at any time
Adjustable chime and audio volume

Master intercom works with any combination of up to three door, sub-master, or master intercoms (sold separately) to enable audio communication with visitors and other rooms within the building
Three buttons with LED indicators allow the master intercom operator to direct a call and communicate with the desired door or sub-master intercom
Privacy button prevents other intercom users in the system from overhearing a conversation with another intercom
Listening feature allows the master intercom operator to receive audio transmission from a door or sub-master intercom at any time
Adjustable chime and audio volume

Master intercom works with any combination of up to three door, sub-master, or master intercoms (sold separately) to enable audio communication with visitors and other rooms within the building
Three buttons with LED indicators allow the master intercom operator to direct a call and communicate with the desired door or sub-master intercom
Privacy button prevents other intercom users in the system from overhearing a conversation with another intercom
Listening feature allows the master intercom operator to receive audio transmission from a door or sub-master intercom at any time
Adjustable chime and audio volume

Specs

In the Box:

Aiphone LEF-3 Open Voice Selective Call Master Intercom, Accepts Up to Three Connecting Door, Sub-Master, or Master Intercoms (Open Box)