Aiphone NEM-20-LD 20-Call Master For Long Distance

20-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:
20-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