This Recommendation | International Standard specifies a representation of an instance of the W3C XML Information Set using binary encodings. These binary encodings are specified using the ASN.1 notation and the ASN.1 Encoding Control Notation (ECN).
ITU-T X.891-2005 history
2005ITU-T X.891-2005 Information technology Generic applications of ASN.1: Fast infoset Study Group 17