Every router has a configuration page where the user can change and alter settings to personalize his or her wireless network for the best conditions.
Dual band routers can broadcast on both bands- 2.4 Ghz and 5 Ghz, you just need to use a different user name and password for 2.4 Ghz and 5 Ghz.
If you’re not sure whether your router is dual band, you can look up its model number on the manufacturer’s website.
To enable 2.4 Ghz settings on your router, follow the steps.
Get the IP address of router. To get the IP address, refer the website: http://www.howtogeek.com/233952/how-to-find-your-routers-ip-address-on-any-computer-smartphone-or-tablet/
Enter the IP address in a browser.
Login with your username and password - Typically, it will be Username: admin Password: blank or admin
Click Advanced Settings tab.
Click Network Settings.
Enable the 2.4 Ghz band.
This can vary from router-to-router, though. Visit Set Up Router for more information.