HL7 v2.3.1 Vocabulary
0.1.0 - ci-build

HL7 v2.3.1 Vocabulary, published by HL7/FO. This guide is not an authorized publication; it is the continuous build for version 0.1.0 built by the FHIR (HL7® FHIR® Standard) CI Build. This version is based on the current content of https://github.com/frankoemig/hl7.v2.terminology.v231/ and changes regularly. See the Directory of published versions

## CodeSystem: Alternate Character Set Handling Scheme (2.3.1 - 1.0.0) (Experimental)

Official URL: http://terminology.hl7.org/v2plusvocab/CodeSystem/alternateCharacterSetHandlingScheme | Version: 1.0.0
Active as of 2026-01-27 | Computable Name: AlternateCharacterSetHandlingScheme
Other Identifiers: OID:2.16.840.1.113883.18.216
Copyright/Legal: HL7 Inc., 2026

HL7-defined code system of concept that specify the scheme used when any alternative character sets are specified in the second or later iterations of MSH-18 Character Set, and if any special handling scheme is needed. Used in HL7 Version 2.x messaging in the MSH segment.

This Code system is referenced in the content logical definition of the following value sets:

- Hl7VSalternateCharacterSetHandlingScheme

Properties

This code system defines the following properties for its concepts

Name | Code | URI | Type | Description
versionIntroduced | versionIntroduced | http://terminology.hl7.org/v2plusvocab/CodeSystem/Property#versionIntroduced | string | version when was this code introduced
versionDeprecated | versionDeprecated | http://terminology.hl7.org/v2plusvocab/CodeSystem/Property#versionDeprecated | string | version when was this code deprecated
status | status | http://hl7.org/fhir/concept-properties#status | code | A code that indicates the status of the concept. Typical values are active, experimental, deprecated, and retired
comment | comment | http://terminology.hl7.org/v2plusvocab/CodeSystem/Property#comment | string | A string that provides additional detail pertinent to the use or understanding of the concept
usage | usage | http://terminology.hl7.org/v2plusvocab/CodeSystem/Property#usage | string | usage notes for this code
modified | modified | http://terminology.hl7.org/v2plusvocab/CodeSystem/Property#modified | dateTime | date of last modification

Concepts

This case-sensitive code system `http://terminology.hl7.org/v2plusvocab/CodeSystem/alternateCharacterSetHandlingScheme` defines the following codes:

Code | Display | Definition | versionIntroduced | comment | modified
2.3 | The character set switching mode specified in HL7 2.3 | The character set switching mode specified in HL7 2.3, sections 2.8.28.6.1, and 2.9.2. | 2.3.1 | Note that the escape sequences used in this mode are "HL7 escapes sequences" as defined in HL7 2.3, sec. 2.9, and do not use the ASCII "esc" character, as defined in ISO 2022-1994 | 2023-10-04
ISO 2022-1994 | This standard is titled "Information Technology - Character Code Structure and Extension Technique". | This standard is titled "Information Technology - Character Code Structure and Extension Technique". | 2.3.1 | This standard specifies an escape sequence from basic one byte character set to specified other character set, and vice versa. The escape sequence explicitly specifies what alternate character set to be evoked. Note that in this mode, the actual ASCII escape character is used as defined in the referenced ISO document. As noted in 1.6.1., escape sequences to/from alternate character set should occur within HL7 delimiters. In other words, HL7 delimiters are basic one byte characters only, and just before and just after delimiters, character encoding status should be the basic one byte set. This value is allowed only for HL7 v. 2.3.1. | 2023-10-04