UCS uses 31 bits for character storage

Contains all known characters and symbols

First 128 characters are the same as ASCII

First 256 characters are the same as ISO-8859-1

Unicode 3.0 describes the BMP (Basic Multilingual Plane) (16 bits)

Unicode 3.1 describes other planes (21 bits)

Characters are ordered in language/script blocks: Basic latin, Cyrillic, Hebrew, Arabic, Gujarati, Runic, CJK etc.

Encoding in numerous encodings: UCS-2, UCS-4, UTF-8, UTF-16 etc.