Allessandro,
The data export from MP70 via the RS232 using the RJ45 connection interface is going to be tricky. I am trying to understand what are you trying to achieve.

A french company Capsuletech, Inc provides the middleware interface for the IntelliVue MP70. Datacaptor 5.0 is the main application and then you have to download the appropriate DDI (device driver interface).

Now if you were an EMR or HIS vendor and wanted to interface with Datacaptor they would provide you with an API.

I think the API is developed on the .net platform on either C# or C++. There IS NO JAVA API.
For you to use interface MP70 with Java you will have to consult wth the Philips Data Export protocol where the output data is in Hexadecimal format and needs to be converted into a more understandable format i.e. XML.
Once in XML it would be more easier to read the data. But again what parameters are you looking at?