I would recommend you to look at Serial to Ethernet Connector. This software will hopefully be the solution you seek. Please, be informed that Serial to Ethernet Connector allows you to share an unlimited number of serial ports devices over network easily turning your computer into low-cost terminal server. Thus, any serial port device connected to a COM port can be accessed from anywhere in the world (via Internet or LAN) as if it is attached directly to the remote PC.
To read more about its features, please visit the page: http://www.eltima.com/products/serial-over-ethernet/
To download free trial version and test its functionality yourself, please follow the link: http://www.eltima.com/download/serial-over-ethernet/