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Z39.50 Access to California Public and Other Libraries
The Z39.50 Information Retrieval Protocol (Z39.50/ISO 23950), is a computer protocol that defines a standard way for two computers to communicate for the purpose of information retrieval. A Z39.50 implementation enables one interface to access multiple library catalogs providing the end-user with nearly transparent access to other systems.
The protocol specifies formats and procedures governing the exchange of messages between a client and server enabling the client to request that the server search a database and identify records which meet specified criteria, and to retrieve some or all of the identified records.
Individuals may use Z39.50 with standalone client software which is available in both commercial and open source versions, or may use a web-based gateway that still uses Z39.50 but accepts input and presents record output in a web browser.
Several California Library Services Act (CLSA) systems have web-based Z39.50 gateways.
Z39.50 clients can also be used to access the California State Library catalog. Complete configuration information is available here:
California State Library Z39.50 Server Specifications (pdf)
Access information for the California State Library catalog, University of California MELVYL catalog and the Library of Congress catalog is listed below:
| Host | IP | Port | Database Name |
| California State Library | vax.lib.state.ca.us | 210 | Marion |
| MELVYL | 128.48.111.102 | 210 | CDL90 |
| Library of Congress | z3950.loc.gov | 7090 | Voyager (Books database) |
Some software products for retrieving and managing bibliographies utilize Z39.50 to connect to library catalogs. If the library's catalog configuration information is not already available on the vendor's website the Z39.50 configuration information can be used to establish a custom setup.
Access information for public library catalogs is available here:
Z39.50 Connection Information for California Public Libraries (pdf)
This data is updated on a regular basis; please contact Ira Bray, ibray@library.ca.gov for corrections or additions.
(Documents in PDF format can be viewed with the Adobe Acrobat Reader.)