This article explains how to connect alarm input and output wires on IP cameras that support alarm I/O (input/output). These ports allow the camera to trigger or respond to external devices such as sirens, strobe lights, or motion sensors.
TABLE OF CONTENTS
- Example Use Cases
- What You'll Need
- Alarm Wire Color Mapping (Pigtail Reference)
- Connecting Alarm Input Devices
- Connecting Alarm Output Devices
- Configure Alarm in the Web Interface
- Pro Tips
Example Use Cases
- Trigger a recording when a door contact sensor opens (alarm input).
- Activate a siren when motion is detected (alarm output).
- Flash a strobe light when a tripwire event occurs on the camera (alarm output).
What You'll Need
- A compatible Lorex IP camera with alarm I/O support (look for labeled pigtail wires)
- Alarm input or output devices (for example: door contacts, motion sensors, buzzers)
- Power supply (12VDC, 24VAC or PoE depending on your model)
- Electrical tape (for waterproofing wire connections)
- Optional: Screwdriver and wire strippers
- Optional: A relay if your alarm device uses more than 12V
Alarm Wire Color Mapping (Pigtail Reference)
Use the following color-coded guide to identify the alarm wires on your camera's pigtail:
| Wire Color | Function | Description |
|---|---|---|
| Brown | ALARM_OUT | Sends signal to trigger an external device (for example: strobe, siren) |
| Green | ALARM_OUT_GND | Ground connection for ALARM_OUT |
| Blue | ALARM_IN1 | Receives input signal from a sensor (for example: door contact). |
| White | ALARM_IN2 | Optional second input signal (if using two sensors). |
| Gray | ALARM_IN_GND | Ground for both input wires |
Connecting Alarm Input Devices
- Identify the ALARM_IN1 and ALARM_IN_GND wires on the pigtail.
- Connect your input device (for example: a door sensor):
- One wires goes to ALARM_IN1
- The other wire goes to ALARM_IN_GND
Understanding Input Logic:
- Logic "1" (HIGH): Input if left unconnected or connected to +3V to +5V
- Logic "0" (LOW): Input is grounded (closed circuit)
Example:
Connecting Alarm Output Devices
The alarm output port lets your camera activate external devices (like buzzers or lights) when an alarm event is triggered.
There are two connection methods:
Mode A: Level Trigger (with Pull-Up Resistor)
- Output toggles between HIGH and LOW based on alarm status
- Requires a pull-up resistor (typically 10KΩ)
- Max load: 12V, 300mA
- Typical use case: triggering low-power devices directly
Wiring Diagram:
Mode B: Switch (Relay Control)
- Alarm output behaves like an on/off switch
- Suitable for direct control of relay circuits or devices
- Max output: 12V, 300mA
- Use a relay for devices over 12V
- Typical use case: Controlling a 24V strobe or industrial siren using a relay
Wiring Diagram:
Configure Alarm in the Web Interface
- Log in to your camera through its IP address.
- Navigate to Alarm Settings
- Set the input type:
- NO (Normally Open) = logic "0" is idle, triggers on logic "1"
- NC (Normally Closed) = logic "1" is idle, triggers on logic "0"
- Set the output behavior depending on your alarm type and action needed.
Pro Tips
- Waterproof all cable joints with electrical and waterproof tape to prevent corrosion or shorts.
- Do not exceed 300mA on alarm output. Use a relay for high-powered devices.
- Always double-check voltage ratings to avoid damaging the camera or connected equipment.
- Test alarm triggers in your camera's interface before permanently installing your alarm device.
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