Specifications

Section 2: System Description
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2.13 DOOR CONTROL CONFIGURATIONS
There are many possible reader configurations. Because of their bidirectional properties, a
single proximity reader may be used to both enter and exit a controlled area. Separate readers
must be used on a door to allow anti-passback control. When a reader is installed on one side
only, a pressure sensitive mat, panic bar, motion detector or other device can be used to send
a request-to-exit signal to the ACU.
A REX switch used in conjunction with a door switch allows the ACU to distinguish a normal entry
from a forced entry; if a REX signal does not precede a door switch, the ACU will report DOOR
FORCED OPEN.
The Alto 818 can be configured to unlock a door when triggered by a REX signal. The door unlock
time is the same as when access is granted through a reader or keypad. The time interval may
be extended by repeatedly activating the REX input. I
The following sections describe configurations for a one-reader door and a two-reader door.
2.13.1 ONE-READER CONTROL
A basic door configuration with controlled entry only is shown in Figure 2-15. A DigiReader
connected to the Alto 818 S-Net RS-485 port controls entry; S-Net power is provided by an Alarm-
Saf supply. Two switches, a REX and door switch, are connected to the ACU through an MSM
on a sensor port. A one-reader system cannot support anti-passback control.
Figure 2-15: Example of One-Reader Door Control Configuration