Thanks John,
Actually, I finally got a bit information on it after some search through the internet. It turns out Rc is an ISO thread code. R is taperred male thread and Rc is taperred female thread. 1/2 is, well, 1/2". This is of course based on British Standard Pipe Thread (BSPT, now that's a familiar term). As for the dia. 35, I have no clue why it's there. Thanks for you suggestion though.
sincerely