The LEF-3 is a selective calling open voice style master station with the capacity of up to 4 total stations. The system can be designed to meet a wide variety of needs, including any combination of master and sub stations up to its maximum capacity. Incoming calls from a sub or door station are annunciated with a momentary electronic mono-tone and an LED, remaining lit for approximately 20 seconds.

Communication at the calling master is press-to-talk, release-to-listen. Person at the receiving station speaks hands free. The person at the master station can selectively call and talk with a person at any other sub or master station in the system. The privacy feature on the master and selected subs prevents eavesdropping from the master station. A call can be received, but communication back to the calling master will be heard only after the privacy button is disengaged. Master stations can be wall or desk mounted.

Sub stations are available in surface or flush mount styles, with or without privacy. Outdoor stations are available in surface or flush mount styles. A vandal proof sub station is also available.