Ethernet cable and a 3G/4G USB modem. 
  operate  in  the  3G/4G  Router  Mode  when  only  detecting  a  3G/4G  USB 
modem. 
  toggle to the Wireless Router Mode when only detecting an Ethernet cable. 
If the Auto-switch System Mode and Ethernet Priority are selected, system 
will: 
  prioritize the Wireless Router Mode when detecting the coexistence of an 
Ethernet cable and a 3G/4G USB modem. 
  toggle  to  the  3G/4G  Router  Mode  when  only  detecting  a  3G/4G  USB 
modem.   
  operate  in  the  Wireless  Router  Mode  when  only  detecting  an  Ethernet 
cable.