This document specifies a set of JavaScript Object Notation Encoding Rules (JER) that may be used to derive a transfer syntax for values of types defined in Rec. ITU-T X.680 | ISO/IEC 8824-1, Rec. ITU-T X.681 | ISO/IEC 8824-2, Rec. ITU-T X.682 | ISO/IEC 8824-3 and Rec. ITU-T X.683 | ISO/IEC 8824-4. It is implicit in the specification of these encoding rules that they are also to be used for decoding.

The encoding rules specified in this document:

–      are used at the time of communication;

–      are intended for use in circumstances where interoperability with applications using JSON is the major concern in the choice of encoding rules;

–      allow the extension of an abstract syntax by addition of extra values for all forms of extensibility described in Rec. ITU-T X.680 | ISO/IEC 8824‑1.

This document also specifies the syntax and semantics of JER encoding instructions, as well as the rules for their assignment and combination. JER encoding instructions can be used to control JER encoding for specific Abstract Syntax Notation One (ASN.1) types.