VMAX IP G4 Relay and Alarm Wiring

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Affected Roles: All Users

Complexity: Medium

Last Edit: July 29, 2026

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Overview

The DW-VG49xT4P VMAX IP G4™ NVR provides alarm input and relay output functionality for connecting external devices such as alarm sensors, door contacts, and external notification devices.

This article explains the difference between:

Sensor Alarm Inputs
Camera Alarm Events
Relay Output
RS-485 Communication

Supported/Affected Devices

Vmax IP G4 Series

Terminal Overview

The available alarm input, relay output, and RS-485 configurations vary depending on the NVR model and channel configuration. The table below summarizes the supported configurations shown in the product specifications.

Model	Video Channels / PoE Channels	Alarm Inputs	Relay Outputs	RS-485 Communication
DW-VG416xT6P	16 channels PoE	8 alarm	4 relay	RS-485 (A/B)
DW-VG412xT8P	8 channels PoE + 4 additional channels	4 alarm	1 relay	RS-485 (A/B)
DW-VG49xT4P	4 channels PoE + 5 additional channels	4 alarm	1 relay	RS-485 (A/B)

For this example, the DW-VG49xT4P rear panel is used to demonstrate the separation between alarm inputs, relay output, and RS-485 communication terminals.

The rear panel provides dedicated connections for each function, as shown below.

Alarm Input / Relay Output Terminals:

COM1   NO1   GND   GND   IN1   IN2   IN3   IN4

RS-485 Communication Terminals:

A      B

Terminal Functions

Terminal	Function
COM1	Relay Common
NO1	Relay Normally Open (NO) Output
GND	Alarm Input Ground
IN1–IN4	External Alarm Sensor Inputs
A/B	RS-485 Serial Communication

NVR Alarm Configuration

After completing the physical wiring, the NVR must be configured to recognize the alarm input and/or activate the relay output.

The configuration can be completed either:

Directly at the NVR
Through the NVR Web Interface

Directly at the NVR

Right-click on the live view screen.
Select: Menu > Alarm
Select the required alarm option:

Sensor: Select Sensor (alarm input) when using an external alarm device connected to the NVR alarm input terminals:

Examples:

Door contacts
External alarm sensors

Configure the required settings, such as:

Alarm input channel
Sensor type (N/O or N/C)
Associated camera
Relay output (if required)

Camera Alarm: Select Camera Alarm when using camera events to trigger an action.

Examples:

Motion detection zone
Relay output

Through the NVR Web Interface

Log into the NVR Web Interface.
Select: Setup > Alarm
Select the required alarm option:

Sensor for external alarm inputs (IN1-IN4)
Camera Alarm relay output activation (Motion detection zones can only be configured directly on the NVR or through the camera’s web interface.)

Configure Recording Schedule

After configuring the alarm settings, the recording schedule must be configured so the camera records when the alarm occurs.

Directly at the NVR

Right-click on the live view screen.
Select: Menu > Record > Schedule
Select the camera channel(s).
Select the desired recording mode:

Through the NVR Web Interface

Log into the NVR Web Interface.
Select: Setup > Record > Schedule
Select the camera channel(s).
Select the desired recording mode:

Recording Schedule Color Reference

Recording Type	Color
Recording Off	White
Continuous	Yellow
Continuous + Motion	Light Blue
Motion	Green
Continuous + Sensor	Red
Sensor	Orange
Motion + Sensor	Purple

Example 1: Sensor Alarm

A door contact is connected to the NVR alarm input (IN1 and GND).

The NVR is configured:

Alarm Setting:

Sensor Alarm enabled
Input type configured as N/O or N/C depending on the door contact

Recording Schedule:

Select Sensor recording mode

Operation: When the door contact is triggered:

The NVR detects the alarm input.
The associated camera starts recording.
The recording continues according to the configured alarm dwell time.

In this example, the alarm input is used to trigger recording only.

Example 2: Camera Alarm with Relay Output

A camera is configured for motion detection, and the NVR relay output is connected to an external device, such as a light.

The NVR is configured:

Alarm Setting:

Camera Alarm enabled
Relay Output 1 selected

Recording Schedule:

Select Motion + Sensor if recording is required for both motion events and alarm inputs.

Operation: When motion is detected:

The camera sends the motion event to the NVR.
The NVR activates the relay output.
The relay closes COM1 to NO1.
The connected device (example: 12V light) turns on.

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