[Intertechno] Support for Intertechno V3 protocol

Every test ist highly appreciated, because the former systems should even work as before. So your test will be valuable.
Please be aware, that I addressed two issues. This one mentioned here to support the V3 Interrechno protocol and another one (with its own thread here) concerning a race condition with the CUL transport. If you are willing to test both, it would be great. Your system should be working as expected as before.