HL7 v2.5.1 Vocabulary
0.1.0 - ci-build

HL7 v2.5.1 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.v251/ and changes regularly. See the Directory of published versions

## CodeSystem: Encoding (2.5.1 - 1.0.0) (Experimental)

Official URL: http://terminology.hl7.org/v2plusvocab/CodeSystem/encoding | Version: 1.0.0
Active as of 2026-01-27 | Computable Name: Encoding
Other Identifiers: OID:2.16.840.1.113883.18.185
Copyright/Legal: HL7 Inc., 2026

HL7-defined code system of concept identifying the type of encoding used to represent successive octets of binary data as displayable ASCII characters. These are defined by IETF; more information may be found at https://www.ietf.org/rfc/rfc1521.txt. Used in HL7 Version 2.x messaging in the ED datatypes.

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

- Hl7VSencoding

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/encoding` defines the following codes:

Code | Display | Definition | versionIntroduced | Deutsch (German, de)
A | no encoding | No encoding - data are displayable ASCII characters. | 2.3 | keine Kodierung
Base64 | Encoding as defined by MIME (Multipurpose Internet Mail Extensions) standard RFC 1521. | Encoding as defined by MIME (Multipurpose Internet Mail Extensions) standard RFC 1521. Four consecutive ASCII characters represent three consecutive octets of binary data. Base64 utilizes a 65-character subset of US-ASCII, consisting of both the upper and | 2.3 |
Hex | Hexadecimal encoding | Hexadecimal encoding - consecutive pairs of hexadecimal digits represent consecutive single octets. | 2.3 |