The LEF is a selective calling open voice style master station with the capacity of up to 4 and 6 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-tome 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 LEF-3C and LEF-5 can activate door strikes or maglocks, call up CCTV cameras, turn on lights, or control other devices that are triggered by a relay. (Requires RYPA relay accessory).