Iphone 4S connects at McDonald's and formerly connected at home how can resume wifi home connection

My iphone 4S connected to the Cisco wireless router in my home without problems. Last night I dined at Applebee's and connected to the restaurant's wifi service. When I returned home I discovered that the iphone would no longer connect with the home wireless network. The error message "Unable to connect" pops up. A laptop computer, printer, and tv are still connected to the same home wireless network. Only my wife and my iphones will not connect. We both connected to the Applebee's wifi. I have reset the network connection several times with negative results. Any suggestions on how I can reconnect the iphone to the home network? Thanks