Bibi-12,

If you are not a hard-core programmer and familiar with UDP, I would recommend going the Global Cache route as it will allow you to communicate asynchronously using TCP/IP (Port 9001 if I remember correctly) and you don't have to deal with RFX-9600, assuming you have one. Plus, you won't have to worry about the signin/signout and all the stuff that appears to be required with their UDP-based control protocol.

I have written several threads about 2-way RS232 via an RFX-9600 and the issues one can face and what a pain it is to guarantee that you don't lose characters in the receive buffer when sending a command.

Search for keyword UART and you will find at least one of them.