9 Pin Serial to Ethernet convertion ( to connecto to a router)

We want a project to convert 9 Pin Serial Port to Ethernet to connect it to a Router. There are some cables available in the market those like 9 Pin to Ethernet. We tried that but when we connect it to the Router, there should be light should be indicating that it has received the signal. But it doesn't. We need a clean device or project that will resolve our problem. We have got two terminals. One PC with 9 Pin Serial Port and other part is a Microcontrol device with 9 Pin Serial port. it used to be cable connected. it still works. But we like to introduce Wireless Point to Point link. Therefore, we need Ethernet and IP protocol. You have to provide us code and manufacturing technique, in case we need another one or to repair the system.