Karl, I address you specifically since your used your smartphone recently to read the first QR code I posted.
Since you reported back your findings, I have downloaded the app to my Windows phone. And it seem to work as planned etc. - apart from the fact that the O umlaut ( ö ) does not show correctly - I get a black question mark on a white diamond.
Can you suggest what I should do on my phone to allow the extended ASCII character set to show ?