Encoding which differs from ASCII even for letters
<p>Are there any character encodings out there which are reasonably common on consumer devices (as opposed to mainframes) and which map the letters <code>A-Za-z0-9</code> different to ASCII?</p>

<p>Currently I'm thinking about a Java application, so I wonder whether there are any chances that a casual user of some Java software in some country could end up with <a href="http://docs.oracle.com/javase/7/docs/api/java/nio/charset/Charset.html#defaultCharset()" rel="nofollow"><code>defaultCharset</code></a> being reported in such a way that <a href="http://docs.oracle.com/javase/7/docs/api/java/lang/String.html#getBytes()" rel="nofollow"><code>"AZaz09".getBytes()</code></a> returns something different than <a href="http://docs.oracle.com/javase/7/docs/api/java/lang/String.html#getBytes(java.lang.String)" rel="nofollow"><code>"AZaz09".getBytes("UTF-8")</code></a>. I'm trying to work out whether I have to address certain compatibility issues which might result from a different behavior in this respect.</p>

<p>I know that historically, EBCDIC would be the prime example of an ASCII-incompatible encoding. But is it being used on any recent consumer devices, or just IBM mainframes and vintage computers? Does the legacy of EBCDIC live on in some country's common encodings?</p>

<p>I also know that UTF-16 is ASCII-incompatible, and that it's quite common to encode files that way on Windows. But as far as I can tell, that's always just file content, not the default application locale. Is it possible for users to configure their Windows machine to use UTF-16 as the system codepage without breaking at least half the applications?</p>

<p>As far as I can tell, all the pre-Unicode muti-byte encodings use in Asia still map the ASCII range 00-7F to something which is compatible to ASCII at least for the letters and digits. Is there any Asian encoding still in use which uses more than a single byte for <em>all</em> its codepoints? Or perhaps on some other continent?</p>