@robert-hh, @jcaron Thanks again for the reply. I knew about the possability to build own firmware but i don't know how to do that and it's going way to far. So i will use the RTM module and multiplex the pins. Haven't tried it yet because actual i'm doing my Bachelor Thesis and i don't have much time for personal projects.

My problem with attach & connect is that examples in the docs like lte.attach() while not lte.isattached(): time.sleep(0.5); print('Attaching...') can get stuck looping forever, the modem never actually attaches or connects. I wanted to write a function that I can call when I want to attach or connect that tries a fixed number of times then resets the modem &/or the gpy. To do this I need a way to pass the attach or connect cmd to the function. Speaking more broadly I would have thought that the basic requirements of something like a gpy in a battery powered application were pretty obvious. Wake up, use the lte to upload some data, quit if you can't get a connection in a reasonable time, sleep, repeat. After a month with this device I'm still no closer to that basic objective.