Susan, you're right. An RJ-11 is just a telephone line, for going between your phone socket and the router. Just plug it into the phone socket as you usually do with a phone (take a plug out of another socket to see which side up to put it), and then on the router side, it'll say either "RJ11" or probably have a telephone icon above the socket you need. In either case, it'll only fit one of the sockets on the back of the router, beacuse the others will be labelled 1 to 4 perhaps (if the router has 4 ports), and those are for RJ45 connections, which are slightly larger.