How does OCLC obtain circulation information from my ILS?
Circulation information including item location, call number, status and OPAC links is retrieved using screen scraping or Z39.50. The method used depends on information available to OCLC about your library’s current services. WorldCat Local “quick start” and WorldCat Local communicate with ILSs using the OCLC control number in catalog records. For this reason, your library must index the OCLC control number in a consistent manner with consistent prefixes in order for the system-to-system communication to occur. OCLC plans to add local system numbers as a future way for WorldCat Local to communicate with your local system.