Here’s to disable Wi-Fi on Zyxel VMG1312 / VMG8924:
1. Using a computer connected to the Zyxel router, open an Internet browser and type 192.168.1.1 to log in to the web-based control panel.
2. When prompted, enter the username: admin and password: 1234
3. Click Wireless Setup –> 4GHz –> Basic Settings –> select Disable for Wireless Radio –> Apply.
NOTE: If your router is Dual Band, you need to disable both the 2.4Ghz and 5Ghz wireless bands.