Originally developed for use in computer communications networks using Open Systems Interconnection (OSI) protocols, ANSI/NISO Z39.50 is now successfully operational in the environment of the Internet. In 1992, a group of implementors (sponsored by the Coalition for Networked Information) established the Z39.50 Interoperability Testbed (ZIT) to make Z39.50 implementations work over the Internet, and to identify and address issues of interoperability among Z39.50 implementations.
Interoperability testing of various Z39.50 implementations through the ZIT made it clear that the transport services (i.e., the Transmission Control Protocol/Internet Protocol [TCP/IP]) of the Internet could be used successfully for the protocol. Using Z39.50 over the Internet is a major step forward. The Internet is a widely deployed network of networks connecting several million host computers and millions of users worldwide. The protocol suite that supports the Internet (i.e., TCP/IP) is readily available and used; it is a ubiquitous connectivity tool. The Internet is home to massive stores of key information resources and connects millions of users that need to access those resources.