How to Connect an Intercom to a Gate Motor (Complete Wiring Guide)

By Alectra Solutions · 15 February 2026 · 4 min read
How to Connect an Intercom to a Gate Motor (Complete Wiring Guide)

How to Connect an Intercom to a Gate Motor

One of the most useful security upgrades for a South African home is connecting your intercom to your gate motor, so you can see and speak to a visitor at the gate, then press a button on the indoor handset to open the gate without leaving the house.

This guide explains how the connection works and how to wire it up for common gate motor brands.

How the Intercom–Gate Motor Connection Works

The intercom does not control the gate motor using high voltage. Instead, it triggers the gate motor via a dry contact relay, essentially a momentary electrical switch that mimics pressing the gate remote button.

When you press "Open Gate" on the indoor intercom handset:

  1. The intercom unit closes a relay contact for 1–2 seconds
  2. This sends a trigger signal to the gate motor's control board
  3. The gate motor interprets this as a "trigger" command and opens or closes the gate

This is the same mechanism used by keypads, fingerprint readers, and access control systems.

What You'll Need

  • Intercom system with a trigger output / relay output (check your intercom manual, most wired video intercoms include this)
  • Access to the gate motor's control board (inside the motor housing)
  • 2-core cable (low voltage, 12–24V) to run between the motor and the intercom outdoor unit
  • Basic electrical knowledge and screwdrivers

Wiring Instructions by Gate Motor Brand

Centurion Gate Motors (D3, D5, D6, D10)

Centurion motors include a clearly labelled TRG (Trigger) terminal on the control board:

  1. Open the motor housing and locate the control board
  2. Find the terminals labelled TRG and 0V (common/ground)
  3. Run your 2-core cable from these terminals to the outdoor intercom unit
  4. Connect one wire to the intercom's relay output terminal and the other to ground/common
  5. Test by pressing the open button on the indoor handset, the gate should respond

ET Nice Gate Motors (Robus, Vela, Dea)

ET Nice motors use similar trigger terminal labelling:

  1. Open the motor housing and locate the PCB
  2. Find the PED or TRG terminals (pedestrian/trigger input) and COM (common)
  3. Connect your 2-core cable: one wire to TRG/PED, the other to COM
  4. At the intercom outdoor unit, connect to the relay output terminals

Gemini Gate Motors

Gemini motors have a trigger/remote input terminal:

  1. Locate the control board inside the housing
  2. Find the terminals marked TRIG and 0V or GND
  3. Connect the intercom relay output across these terminals

Cable Requirements

The trigger cable carries very low voltage (typically 12–24V DC from the intercom) and very low current. You can use standard 2-core alarm cable or security cable, the same type used for the intercom itself.

Maximum recommended cable run: 100m for most systems. Longer runs may require a relay booster.

Tip: If your intercom outdoor unit is mounted at the gate right next to the motor, you may be able to connect directly inside the motor housing, keeping the installation neat.

Testing the Connection

  1. With the gate motor powered on, press the "open/trigger" button on the indoor intercom handset
  2. The gate should activate as if triggered by a remote control
  3. If nothing happens, check: (a) correct terminals used, (b) relay output is enabled in intercom settings, (c) no loose connections

When to Use a Professional

This is a straightforward connection for anyone comfortable with basic electrical work. However, if you're unsure about accessing the motor control board or running cables, an automation technician can typically complete this connection in 1–2 hours.

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