Thank you for your answers.
When I type “v” or “?” in minicom nothing happens (same when pressing enter afterwards). I’ve just reinstalled raspbian jessy and it didn’t change anything. https://community.openenergymonitor.org/t/rfm69pi-getting-started-basic-question/260 There I could read that sending a ? will list all available commands… it won’t work for me. It doesn’t even seem like I can type anything at all, minicom is just listing the lines mentioned above. Only thing that works is strg+a + z. I can then use all options listed in the help screen, but I do not see a single way there to configure the RFM69Pi.
I can not find any descriptions on the internet about a “?” command like: http://manpages.ubuntu.com/manpages/xenial/man1/minicom.1.html