Unicode is a standard for representing text from multiple languages. Each glyph is represented by a 32-bit code point, commonly written as U+nnnn or U+nnnnnnnn. The x3270 family uses Unicode as the internal representation of all text data. (It also retains EBCDIC text sent from the host, but the process of displaying it involves translations to and from Unicode.)
Text read by the emulators is converted to Unicode internally. When text is displayed, it is converted from Unicode to the workstation's local encoding.
The most common encoding for Unicode is UTF-8. UTF-8 uses a single byte to represent ASCII characters, and multi-byte sequences to represent code points above U+00ff.
Explicit use of Unicode
The Key() action accepts a Unicode code point (U+nnnn) as a parameter.
The ReadBuffer() action includes a unicode option to produce output as Unicode code points.
The x3270 family only supports the Unicode Basic Multilingual Plane (BMP).