The address for the Patent Classification Home Page on the USPTO intranet is http://ptoweb.uspto.gov/patents/classification-resources/. The Classification Home Page is also accessible from the desktop via the Patent Examiner’s Toolkit. The site is the clearinghouse for classification information published in hyper-text mark-up language (HTML) and Adobe Acrobat portable document format (PDF) by the U.S. Patent and Trademark Office (USPTO). Examiners and the public are provided with access to identical information for the Index, schedules, and definitions.
The Intranet Classification Home Page site also includes links to international information such as IPC Concordance, IPC Schedules, IPC Catchword Index, WIPO Handbook on Industrial Property Information and Documentation, and to national (U.S.) information such as Overview of the Classification System, Classification Guides and Bulletins, and the Patent Classification Search Page.
The Patent Classification Retrieval System (PCRS) provides Original (OR) and Cross-Reference (XR) classification information for individual patents and listings of patents contained in subclasses. This data is updated bimonthly with new issues, withdrawn patents and reclassifications.