It is expected that most of the processing by applications using the ULS will be done using UniChar strings. Yet, many applications will need to export data to and import data from non-UCS encodings (for example, ASCII or EBCDIC). For this purpose, a set of functions are defined to perform conversions between UCS and non-UCS encodings. The Uconv name is used to indicate these functions. The Uconv functions are capable of doing only UCS conversions, such as converting to/from UCS.

In addition, the iconv functions defined by the X/Open Portability Guide, Issue 4 are provided for converting between any encodings, for example, between PC code and ISO codes. In addition, any of the UCS conversions may be invoked using the iconv functions by specifying UCS-2 as the to/from code set.