Interfacing online bibliographic databases with Z39.50

Many online databases are available on the Internet, each one with its own access procedures and a special user interface and query language. The Z39.50 protocol standard offers a solution to this situation of diversity and lacking interoperability. However the majority of online databases do not yet support Z39.50. We describe a system that interfaces online bibliographic databases with Z39.50 clients, if the databases are accessible via TELNET and have a line-oriented interface. Our system thus acts as a gateway or middleware. One part of it is a Z39.50 server which can be accessed by every Z39.50 client. The client's requests are translated into commands of the database's query language, which are then sent to the database via TELNET. The results received from the database are analyzed, transformed into the appropriate Z39.50 protocol data units and sent back to the Z39.50 client. The system is highly configurable and can be adapted to the different features and parameters of online bibliographic databases.