Specifies a set of Packed Encoding Rules that may be used to derive a transfer syntax for values of types defined in ITU-T Rec. X.680 / ISO/IEC 8824-1. These Packed Encoding Rules are also to be applied for decoding such a transfer syntax in order to identify the data values being transferred. The encoding rules specified in this Recommendation / International Standard: are used at the time of communication; are intended for use in circumstances where minimizing the size of the representation of values is the major concern in the choice of encoding rules; allow the extension of an abstract syntax by addition of extra values, preserving the encodings of the existing values, for all forms of extension described in ITU-T Rec. X.680 / ISO/IEC 8824-1.