If you are on a business trip or staying in a hotel, buy a mini router and plug it directly into the telephone interface of the room. Can I use it directly? Does the router need to be set up?

No, the interface of wireless routing is different from that of telephone line. You need to add a moden in the middle, and to ensure that this telephone line has network service, you need to know the account password to meet the needs of internet access. If you want to surf the Internet directly, I suggest you buy a wireless network card and plug it directly into your notebook to surf the Internet.