CallerID with umlauts / special letters

[Starlifter]

Dear Yealink-Support,

I have in use several phones of your company and like them very much. But there is one thing, that my users complain about: the german umlauts aren't recongised by the phones.

But step by step:

As you might know, there are some special language-typical letters out there in the world. In Germany, where I come from, there are f.e. umlauts like "ä" and "ö". There also is a special letter "s" in the german alphabet: "ß".

If one of these letters is part of an incoming caller ID, the Yealink phones (I've tested it with a T38G) doesn't display it. Instead, there will be a questionmark. So, for example, the german name "Müller" (would be Miller in english) is displayed as "M?ller". That's not good. My Aastra phones on the same Asterisk 11 (FreePBX 2.11) machine display the CID correctly.

So I think it is an issue with your phones. They seam not to supoort UTF-8 which they should. Could you please have a look at this?

Thank you!

Greetings from Germany!