Allied Telesis IE340 Series, Installation Manual, Page: 38 / 136

IE340 Series Installation Guide
38
Alarm In Connector
The switch has a 2-pin Alarm In (ALM IN) connector for an external sensor
on the top panel. The switch can use an external sensor to monitor the
wiring room or cabinet for unauthorized access or for changes in the
room’s environment, such as the temperature or humidity. Here are
examples of the types of sensors you can attach to the connector:

Door

Temperature

Motion detector

Light

Humidity
The two pins of the connector, referred to as contact alarm 1 in the
operating system, act as a electrical circuit. The switch places a 3.3VDC
voltage on the circuit and monitors its status, which can be either closed or
open. A closed circuit is on, meaning that voltage can flow through the
circuit, while an open circuit is off, preventing the flow of voltage through
the circuit.
The switch performs one or more of the following functions when the state
of the external sensor changes to open or closed.

Transmits an SNMP trap.

Flashes the Fault LED.

Activates the device on the Alarm Out (ALM OUT) connector.
You use the ALARM FACILITY INPUT-ALARM command in the
AlliedWare Plus operating system to specify the state of the external
sensor that signals an alarm. Alarms remain active until their causes are
resolved. For instructions on the command, refer to the
Software
Reference for IE340 Switches
.
Here are the requirements for the external sensor:

It must be a dry contact.

It must not place any current on the circuit.

It must not use the voltage or current for its own operations.

It must be able to handle a minimum of 3.3VDC and 320uA.
Caution
The external sensor might damage the Alarm In connector if it
places a voltage on the circuit.
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