when it s not connected to wifi by Ethernet it flashes red which means it doesn t work. if it s connected and works it flashes green. I don t have a router now so what can I do to make it work?
"I don t have a router now", so if you don't have a router where is the WiFi coming from? WiFi and Ethernet are normally considered as alternative interfaces for connecting devices to a router.
Without knowing what signal booster you are talking about and exactly what it does and how it works, it is not really possible to provide a sensible answer. Perhaps you can add more detail to your question explaining exactly what the configuration is.
No, a phone signal booster does not need to be connected to ANYTHING by Ethernet. I'm guessing you're talking about a microcell. Those do require an internet connection. And no, you can't make it work without.
Well, assuming it is a VoIP booster, you have two options: (these are assuming that you still have a modem too)
1. Buy a router
2. Buy a really long ethernet cable or a powerline networking kit
You cant connect to wifi by Ethernet! Ethernet is wired. Wifi is wireless.
You must be connected to the internet – that is how it works.