What is the Z39.50 Protocol?

Whether you are a season veteran or a new-comer to the world of librarians, you will have probably come across the term Z39.50 or heard talk about Z39.50 servers. This article explains what a Z39.50 server is and how it can be of use to you and your library.

Z39.50 is a protocol (a special set of procedures or rules that specifies the correct procedure for applications to communicate with each other) that helps you to search and retrieve information or records from a bibliographic database. It is commonly used by librarians to search the Online Public Access Catalogues (OPAC) of other libraries. It is often implemented in the inter-library loan

What is InterLibrary Loan?

A service by which a library can borrow books or other resources owned by another library. If a patron desires books that are not in their local library but are available in another library (or libraries) that has an existing inter-library loan arrangement with them, the local library can identify which of the partner libraries has the desired resource and place the request to borrow the item. The local library then receives the resource, loans it out to the patron who made the initial request, and arranges for its return. Depending on the arrangements made by the libraries, the item will have due dates and overdue fees set either by the intermediary local library or the lending library which owns the item. A fee will usually be charged for using the inter-library loaning module.
catalogue searches or when downloading MARC bibliographic or authority records for use in cataloguing.

If a librarian (the client) wants to search for bibliographic records from another library (the server), the Z39.50 protocol initiates and establishes communication between the initiating client application, searches the database or databases of the responding server, and retrieves the relevant information that was requested by the client. The retrieved information is then sent back to the client application and either displayed or made available for download.

Z39.50 is very useful for librarians when they are cataloguing and used when copy cataloguing. Copy cataloguing is a process by which a librarian looks for and retrieves an existing bibliographic record that matches an item they want to catalogue and edits the record to suit their library’s particular standards, and then imports the record into their local holdings. It saves an significant amount of time by allowing librarians to simply copy the work that has been done by other libraries (such as the Library of Congress or British Library), instead of reinventing the wheel and doing everything from scratch. Copy cataloguing uses the Z39.50 protocol to connect to, search and retrieve the desired information from the target library’s database(s).

In order to use the Z39.50 protocol, you must have the relevant connection details and in some cases, access credentials such as usernames and passwords. You will also need a Z39.50 application – some come as standalone applications or it can be integrated into a library system such as Koha ILS.