Good camera but backup ADSL - 3G improve

I use the home router for a backup behind a DSL box problem (in fact, the broadband network regularly jumps sometimes for several hours despite the interventions of all technicians at my ISP, 2 months it lasts!)

I have inserted a key 3G mobile with free unlimited smart and trendy all my fixed network and wifi on the router instead of the box. Everything works fine and I finally have a permanent Internet.

The unit does not heat up and I have a good wifi range with the antenna provided as standard (as good as the box).

By cons, it remains a concern, when the network goes ADSL, 3G network takes well over in seconds but when the ADSL network returns, there is no return on ADSL, 3G remains activated. We must cut off the router's power to turn off 3G (!) I have put the issue to TP-Link but their technicians have not yet answered. So I removed one star.