This part of IEC 61334 defines a set of encoding rules - the A-XDR3) encoding rules - that may be used to derive.the specification of a transfer Syntax for values of types defined in the DLMS core standard using the ASN.1 notation (see IEC 61334-4-41). These A-XDR encoding rules Are also to be applied for decoding such a transfer Syntax in order to identify the data values being transferred.
The A-XDR encoding rules are used at the time of communication; provide optimal4) encoding for DLMS PDUs.
NOTE Provided that A-XDR ensures optimal encoding for DLMS PDUs, it is intended to be the default encoding rufe for DLMS-based communication protocols. Nevertheless, the default - and also the possibly usable optional - encoding rules will be specified in the Application Layer document of the given protocol (for example, IEC 61334-4-42), as part of the Application context.