ISO/IEC 8825-3:2008 defines Encoding Control Notation (ECN): a notation for specifying encodings of ASN.1 types or of parts of types. It provides several mechanisms for such specification, including:
- direct specification of the encoding using standardized notation;
- specification of the encoding by reference to standardized encoding rules;
- specification of the encoding of an ASN.1 type by reference to an encoding structure;
- specification of the encoding using non-ECN notation.
It also provides the means to link the specification of encodings to the type definitions to which they are to be applied.
ECN does not currently provide any support for specifications using the object identifier (OID) internationalized resource identifier type or the relative OID internationalized resource identifier type (see ISO/IEC 8824-1).