Identical to “type of data” component in the reference pointer (RP) data type. (See Section 3.20.3, “Type of data (ID)”). Refer to HL7 Table 0191 – Type of referenced data for valid values.
Note that when MIME type is used in Type of data that readers must treat the values case insensitively as per RFC 2045.
3.10.3 Data subtype (ID)
Identical to “subtype” component in the reference pointer (RP) data type. (See Section 3.20.4, “Subtype (ID)”).
3.10.4 Encoding (ID)
The type of encoding, if present, used to represent successive octets of binary data as displayable ASCII characters. Refer to HL7 Table 0299 - Encodingfor valid values.
Output character positions which are not required to represent actual input data are set to the character “=”. Since all canonically encoded output is an integral number of octets, only the following cases can arise: (1) the final quantum of input is an integral multiple of 24 bits; here, the final unit of encoded output will be an integral multiple of 4 characters with no “=” padding, (2) the final quantum of input is exactly 8 bits; here, the final unit of encoded output will be two characters followed by two “=”padding characters, or (3) the final quantum of input is exactly 16 bits; here, the final unit of encoded output will be three characters followed by one “=” padding character.
Receivers must evaluate this field in a case insensitive manner.
HL7 Table 0290 - MIME base64 encoding characters