Dont try and build it yourself, there are a ton of headaches, ones you don't realize until you actually start implementing and it doesn't quite work.
http://www.solutioninc.com/
I am not affiliated with the company but I know a few of the people working there that developed it (and saw how they were pulling their hair out at times). I have stayed in a few hotels using their product and it just worked.
Dont try and build it yourself, there are a ton of headaches, ones you don't realize until you actually start implementing and it doesn't quite work.
http://www.solutioninc.com/
I am not affiliated with the company but I know a few of the people working there that developed it (and saw how they were pulling their hair out at times). I have stayed in a few hotels using their product and it just worked.