It isn't likely that a wired connection in a hotel would require authentication to get an IP address. Most often, the business will authenticate via a web page AFTER you have accessed the LAN, and before permitting a connection to access the internet.

I haven't used this model but I'm browsing the emulator ( http://www.tp-link.com/us/download/TL-WR810N.html). When you run setup - under WAN connection type, are you not getting an IP address when you "Detect"? If not, there are a couple of things to validate - principally, that the network port in your room is enabled/active. Are you able to connect to the internet by plugging directly into the wired port with a computer?