Integration Services uses transformations to manipulate data during an ETL dataflow. Transformations can be used in [[articles:SSIS Dataflow Task|Data Flow Tasks]], between data source and destination components, or other transformations.

Alphanumeric values are often need transformation during a data flow: converting to upper- or lowercase is the most common case. This can be solved using the Derived Column transformation as well - in combination with the UPPER or LOWER functions.

But Character Map has other features as well: reversing byte order, mapping katakana characters to hiragana characters (and vice versa), mapping half width characters to full width characters (and vice versa). There is an additional transformation - linguistic casing -, which uses an external reference to the Win32 API for Unicode simple case mapping of some locales.

The Character Map transformation supports an input, a regular and an error output.

For more detailed information on this transformation, please refer to this MSDN article.
For the complete list of SSIS transformations, check this Wiki article.