Z39.50

Z39.50 is a U.S. national standard defining a protocol for computer-to-computer information  retrieval. It was developed in 1988 (and revised in 1992) by the National Information Standards Organization (NISO), a standards development body that serves the publishing, library, and               

information services communities. The protocol is often layered over TCP/IP. Internet RFCs  related to Z39.50 include RFC 1729 (Using the Z39.50 Information Retrieval Protocol, December  1994),RFC 1625 (WAIS over Z39.50, June 1994), and RFC 2056 (Uniform Resource Locators for Z39.50, November 1996).