How to write special characters to ADLDS?

[Makayla341]

I'm trying to write contacts into an ADLDS ldap for using them as a phone book for a Yealink T48G. Sometimes the name of the contact includes some special characters like "ö", "ß" and "é". If these characters are contained in the fields "givenName" or "displayName" neither the phone nor the ldap client can show them correctly and instead show some other chars (for example "ö" -> "ö"), however the "name" and "dn" fields show these characters correctly.

If I insert the contactvalues via ADSI-Edit or any other tool, the phone shows the name correctly, but my application is no longer able to read the inserted special chars from givenName and shows some questionmark-boxes, however the dn and name fields are read correctly.

I've already tried using utf-8, utf-16, utf-32, iso-8859-1 and windows-1252 as encoding for my application.

So the question is how can I store these special characters using C# in the givenName property for an inetOrgPerson in an ADLDS instance?

[Christ8]

The issue was resolved by setting the protocolversion that should be kfc survey used to version 3.

Code:

connection = new LdapConnection(new LdapDirectoryIdentifier(host, port));
connection.SessionOptions.ProtocolVersion = 3;