The ISO-ON-TCP connection need TSAP numbers, which I don't have. The TCP link option seem to be the correct one (configuring one link with the port 2000 & "Passive fetch" mode, and another link with the 2001 & "Passive write" mode), but it does not work. In the XBTGT manual states that the screen uses 2 links to communicate with the S7-300, but I don't know how to create & configure them in NetPro.