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​​​​​​​How to Set Up 4G/5G Backup on your TP-Link 4G/5G Deco in Wi-Fi Router Mode

Configuration Guide
Last updated: September 17, 2026

4G/5G Backup allows you to use the SIM card installed in your 4G/5G Deco as a backup internet connection. This feature is available when a 4G/5G Deco is the main Deco and the network operates in Wi-Fi Router mode.

If the primary wired internet connection fails, the main Deco automatically switches to the 4G/5G mobile network to keep your internet online. Once the wired connection is restored, the Deco system automatically switches back.

Key Takeaways

  • 4G/5G Internet Backup uses the SIM card in the main 4G/5G Deco when the wired internet connection fails.
  • The 4G/5G Deco must operate as the main Deco in Wi-Fi Router mode.
  • An active, compatible SIM card and a mobile data plan are required.
  • Deco switches to the mobile network during an outage and switches back automatically when wired service returns.
  • The Deco app lets you manage outage detection, mobile data, SMS, SIM security, and supported external antennas.

Requirements

  • Confirm that the 4G/5G Deco is configured as the main Deco in Wi-Fi Router mode.
  • Insert an active, compatible SIM card with an available mobile data plan.
  • Place the main Deco where it receives a stable 4G/5G signal.

​​​​​​​

Set Up 4G/5G Backup

1. Open the Deco app, go to More > Advanced > Internet Backup.

Locate the More and Advanced option on the page.Locate the Internet Backup feature on the page.

2. Select 4G/5G Backup and enable it.

Locate the 4G/5G Backup feature on the page.Display the 4G/5G Backup settings.

3. (Optional) It is recommended to set a fixed WAN port to ensure that wired clients can connect to the internet when using the backup network.

Note: Go to More > Advanced > WAN Port. Then disable Auto WAN Port and set a fixed WAN port for your Deco.

Locate the WAN Port feature on the page.Locate the Auto WAN Port feature on the page.Display the options for setting a fixed WAN port.

4. (Optional) You can configure the following settings as needed.

  • Offline Detection: Select Single Detection (DNS Lookup) or Dual Detection (DNS Lookup and Ping) to determine when Deco activates the backup connection.

Display options for Offline Detection.Display options for Offline Detection.

  • Internet: Configure the SIM card's internet settings and check the connection status.

Display the Internet settings.Display the Internet settings.

  • Data Settings: Monitor mobile data usage or set a usage limit.

Display the Data Settings.Display the Total Allowance settings.Display the Usage Alert settings.

  • SMS: View, send, and receive messages for the SIM card.

Display the SMS settings page.Start editing a new message.

  • PIN Management: Set a PIN to prevent unauthorized use of the SIM card.

Display the PIN Management settings.A blank space is displayed for entering the PIN Code.

  • External Antennas: Enable this option if external 5G antennas are installed to improve the Deco's 5G signal reception.

The External Antennas button is displayed.

Setup complete!

When the primary WAN connection fails, the Deco network automatically uses the mobile connection provided by the SIM card in the 4G/5G main Deco.

Display the current network status of the Deco network.​​​​​​​

To learn more about each function and configuration, please visit the Download Center to download the manual for your product.

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