P/N 66109923001 Rev. A
1
SCOPE
This manual provides information necessary to install, use and troubleshoot a NexStar RS-485
Multiplexer. It is assumed that the person reading this manual is familiar with access control
systems and standard installation practices. The information provided in this manual is not
intended to conflict with the building, electrical, fire or safety codes required for any given
installation.
INTRODUCTION
The NexStar is a symmetrical 5-port repeater with built-in arbitration logic. Any one port will
relay the data it receives to the other four ports. Bus arbitration is done on a first-come, first-
served basis. During periods of no activity, the NexStar automatically places all 5 ports into the
receive mode to wait for the next message.
The NexStar provides a link between a WSE access control unit, such as the NexSentry or SE
818SC, and multiple S-Net runs. A single S-Net run may be a maximum of 4000 feet (1200
meters). Using all of the NexStar 's five symmetrical ports, the end-to-end S-Net length can
span up to 8000 feet (2400 meters) and contain up to 20,000 feet (6000 meters) of installed
wiring.
4000 FEET
(1200 METERS)
NEXSTAR
DR 4205K
DR 4205K
DR 4205
DR 4208
DR 4204
DR 4204
VIP2
MSRK
ACCESS
CONTROL
UNIT
Figure 1: S-Net Layout using a NexStar
