Z39.50 is an international standard for communication between computer systems primarily, library and information related systems. Z39.50 is important to the development and deployment of inter-linked library systems. The Z39.50 standard was originally proposed in 1984 to provide a standard way of interrogating bibliographic databases. Since then, it has gone through 3 versions - in 1988 (v1),1992(v2) and 1995(v3). Version 2 in 1992 also incorporated and became compatible with an ISO standard (10162/3) called Search and Retrieve. Version 3 in 1995 extended the features of the protocol.
The Z39_50 Asn1API is compliant with :