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Date added 16 May 2007
Last edited 12 November 2009

Full Title

ISO 23950: Information and documentation - Information Retrieval (Z39.50) - Application Service Definition and Protocol Specification


The objective of ISO 23950 (Z39.50) is to facilitate the open interconnection of database users with database providers.

The standard specifies a client/server based protocol for information retrieval. Procedures and structures for database search, record retrieval, and result set scanning and sorting. Support is given to access controls, resource control, extended services and help facilities.

The ways in which databases are implemented differ considerably; different systems have different styles for describing the storage of data and the means by which it can be accessed. A common, abstract model is therefore used in describing databases, to which an individual system can map its implementation. This enables different systems to communicate in standard, mutually understandable terms.

Standards Developing Organisation



No information available.

Lifecycle Action

Access, Use and Reuse

Standard Framework

Digital Archive Standards

Standard Type

Searching Protocols

Current Version

Further Information

Z39.50 International Standard Maintenance Agency [external]
Includes documentation for various versions of Z39.50, resources, profiles and details of ZIG- the Z39.50 User Group

Alternative Current Version

2003 - ANSI/NISO Z39.50 - Information Retrieval : Application Service Definition and Protocol Specification [external PDF]
Maintenance revision of Z39.50-1995, which is equivalent to ISO 23950: 1998

Previous Versions

Referenced Standards

ANSI/NISO Z39.53: 2001, Codes for the Representation of Languages for Information Interchange
ISO 10160: 1991, Information and Documentation - Interlibrary Loan Application Service Definition for Open Systems Interconnection
ISO 10161: 1991, Information and Documentation - Interlibrary Loan Application Protocol Specification for Open Systems Interconnection
ISO 2709: Documentation - Format for Bibliographic Information Interchange on Magnetic Tape
ISO 4217: 1990, Codes for the representation of currencies and funds
ISO 8777: Information and Documentation - Commands for Interactive Text Searching
ISO 8824:1990, Specification of Abstract Syntax Notation one (ASN.1)
ISO 8825:1990, Specification of Basic Encoding Rules for Abstract Syntax Notation one (ASN.1/BER)