Aiphone NEM-10-LD 10-Call Master For Long Distance

10-Call Master for Long Distance/Elevators is designed for communication with remote locations up to 4000' away, or to each elevator in a building.
Features:
10-call master Two-way communication between master and subs Clear communication to subs in elevators
Substations can be up to 4000' away Call-in from sub remains lit on master until answered Master is "push-to-talk", "release-to-listen" Hands free communication at sub stations
Sub stations are weather resistant
Common applications include office complexes, large commercial facilities, gated entries, parking lots and airports
Sub stations are available in surface or flush mount styles require a separate circuit board to be added for the call-in function
 Three wires are required to each sub station