Proximity Card Reader (RS-485)
AC-1100
Technical Reference Manual
Connecting the RS-485 scanner network
The AC-1100 proximity reader is monitored and controlled by its host device via the RS-485
scanner network. A comprehensive discussion of this RS-485 networking system is available
in the RS-485 Wiring Guide, file name
RS-485 HIG Rev A ENG-US.pdf
.
The RS-485 scanner network operates in half duplex mode, with the host device acting as
master and the AC-1100 card readers acting as slaves. Only one master device may be
connected to a group of AC-1100 card readers on the RS-485 scanner network.
The AC-1100 is connected to the RS-485 network via the four-way terminal block fixed in the
resin potting at the rear of the unit. The RS-485 terminals are labeled ‘–’ and ‘+’. Connect all
‘+’ terminals to the ‘+’ line and the ‘-’ terminals to the ‘-’ line of the RS-485 scanner network.
AC-1100
RS-485
- +
Master
Device
RS-485
+
-
RS-485 Scanner Network
Scanner network cabling
The recommended cabling type for the RS-485 scanner network is a shielded cable containing
size 24 AWG, stranded conductors arranged in twisted pairs. Belden P/N 9842 or equivalent,
24AWG 2-pair, shielded cable is an example.
The network cable must be run in a multi-drop fashion from one device to the next.
The position of the host device in the RS-485 scanner network is not important – it may be
located at the end of the network or in the middle.
Where the scanner network exceeds 200 yards, ensure that the devices at the physical ends
are resistively terminated. Do this by placing a 120
Ω
resistor across the network lines (from
+ to – on the connector).
Copyright KeyMatrix Inc.. All rights reserved.
Revision C
[2005-11-04]
p. 10
