6.1.2.5.3 Requirements

The character set specified by value 1 of the Attribute Specific Character Set (0008,0005), or the default character repertoire if value 1 is missing, shall be active at the beginning of each textual Data Element value, and at the beginning of each line (i.e., after a CR and/or LF) or page (i.e., after an FF).

If within a textual value a character set other than the one specified in value 1 of the Attribute Specific Character Set (0008,0005), or the default character repertoire if value 1 is missing, has been invoked, the character set specified in the value 1, or the default character repertoire if value 1 is missing, shall be active in the following instances:

⎯ before the end of line (i.e., before the CR and/or LF)

⎯ before the end of a page (i.e. before the FF)

⎯ before the end of a Data Element value (e.g. before the 05/12 character code which separates multiple textual Data Element Values — 05/12 corresponds to “\” (BACKSLASH) in the case of default repertoire IR-6 or “(” (YEN SIGN) in the case of IR-14 ).

If within a textual value a character set other than the one specified in value 1 of the Attribute Specific Character Set (0008,0005), or the default character repertoire if value 1 is missing, is used, the Escape Sequence of this character set must be inserted explicitly in the following instances:

⎯ before the first use of the character set in the line

⎯ before the first use of the character set in the page

⎯ before the first use of the character set in the Data Element value

⎯ before the first use of the character set in the name component and name component group in Data Element with a VR of PN

Note: These requirements allow an application to skip lines, values, or components in a textual data element and start the new line with a defined character set without the need to track the character set changes in the text skipped. A similar restriction appears in the RFCs describing the use of multi-byte character sets over the Internet. An Escape Sequence switching to the value 1 or default Specific Character Set is not needed within a line, value, or component if no Code Extensions are present. Nor is a switch needed to the value 1 or default Specific Character Set if this character set has only the G0 Code Element defined, and the G0 Code Element is still active.