Lately, we all have been trying to be ready for anything. In case of a power outage, we have generators and charged power banks, and for other critical events, we have a supply of water and food for several days. If you have a problem with home Internet from the provider, you can use the mobile modem function to connect to the Internet through a 4G or 5G connection and distribute Wi-Fi throughout the house. Let’s understand how it works and why it is more effective than just using your smartphone as a hotspot.

All ASUS range extender routers that have a USB port support the mobile modem function with the latest software update. Thanks to it, the user has the opportunity to connect a smartphone to the router and share their Internet connection via 4G or 5G. All that needs to be done is to properly configure the ASUS router so that it receives the main connection through the USB port, and later distributes this connection through the Ethernet cable and also via Wi-Fi to the rest of the devices in our home.

A router with a mobile modem and Dual WAN - how to stay connected when the local Internet does not work

The advantages of using the mobile modem function are quite obvious:

  • You will always be connected to the Internet, even if the fixed fiber optic connection fails. In an emergency, this is one of the best ways to reconnect.
  • There is no need to buy a separate compatible modem or 4G/5G router – any smartphone that supports shared access to the Internet via a USB cable will do. However, we note the need to use “native” smartphone cables, and not cheaper analogs from Aliexpress.
  • You can even use an old mobile that you don’t use every day and that will just sit on all the time because it is powered by USB from the router. We will have permanent Dual WAN.
  • You will have full Wi-Fi coverage with an ASUS router to extend your range and create a complete Wi-Fi Mesh network in your home or office.

But why not simply use a smartphone and not bother with these routers? First, the signal strength and range of Wi-Fi coverage that a smartphone can provide is lower. In addition, we must keep in mind that due to the organization of shared access to the Internet via Wi-Fi, the smartphone heats up a lot and loses battery power very quickly. That is why, the ability to connect a smartphone to a router allows you to combine the functions of two devices most optimally.

A router with a mobile modem and Dual WAN - how to stay connected when the local Internet does not work

Dual WAN in ASUS routers

With the latest router firmware, ASUS router users can automatically connect and share the Internet without additional settings. This Plug&Share feature is ideal for those who don’t want to configure advanced configurations. For small and medium-sized companies that are interested in this feature to ensure a stable Internet connection in any situation, the fine-tuning option in the Dual WAN section will be more interesting.

ASUS has included this feature in all of its routers with a USB port in the WAN / Dual-WAN section. This menu contains all the options available to enable this feature. A very important aspect is that there are two configuration modes to change the behavior of the router for different networks:

  • Failover mode: this configuration mode allows us to have a primary connection to the WAN that will work continuously, and only if it fails for a few seconds or minutes, then the backup connection that you have configured in our case – a second WAN via USB starts working. When the primary Internet connection is restored, traffic will begin to flow again through the primary WAN connection and the secondary connection will go into standby mode.

A router with a mobile modem and Dual WAN - how to stay connected when the local Internet does not work

  • Load balancing mode: this configuration mode allows us to have two internet connections working at the same time, although we can give one of the connection options a higher priority over the other. This mode is recommended only if you have unlimited 4G/5G data speed and your main connection may fail at any moment, or you have very low internet speed from your ISP, as in the case of old xDSL lines.

A router with a mobile modem and Dual WAN - how to stay connected when the local Internet does not work

A very important aspect is setting up Internet connection problem detection. We can adjust the discovery interval for every few seconds and this can be done by DNS query or by pinging a specific IP address like Google’s DNS with its The WAN failover trigger will only be activated when these tests fail a specified number of times continuously to avoid a micro failure causing a failover to a second WAN connection.

Dual WAN settings

The first thing we have to do is to connect the smartphone with a USB cable to the ASUS router. After connecting, we will need to open the USB settings of the mobile phone, click on USB settings and select USB managed by this device and Use USB as a USB modem. After connecting the iPhone to the router using the USB cable included in the kit, you will be prompted to Trust this computer which must be answered with “Trust”.

After a few seconds, the ASUS router will recognize the connection and we can start configuring Dual WAN. The first thing we need to make clear is that the configuration of the main WAN will not be changed at any time – the configuration you made earlier will be preserved without any problems.

In the Dual WAN menu, we can see that the secondary WAN connection has been automatically activated. Under Dual WAN Mode, we have the Failover or Load Balancing options we mentioned above.

At the bottom, we have the “Automatic network discovery” setting so that the router detects whether there has been a disconnection from the Internet or not. This is usually left at the default and chooses between a DNS query and/or ping and determines the destination. In this way, the router will know exactly whether the connection to the Internet has been lost or not, to switch to the second WAN connection.

If we go to the “Internet connection” section, we will see that the WAN type is USB, and below that we will have configuration options, but they are all already set up properly to get started and do not require any additional settings from the user.

Thus, using an ASUS router with a mobile modem function and the ability to configure Dual WAN, you will be ready for any emergency shutdowns of the local Internet and will always stay connected.