The Index to the U.S. Patent Classification System (USPC) is an alphabetic listing of technical and common terms referring to specific classes and subclasses of the USPC. The index is used as an initial entry into the system and should not be considered exhaustive. All appropriate class schedules should be scanned for specifically related subclasses, and the definitions and associated notes of the pertinent classifications should also be reviewed, even when the citation found in the Index appears to be restricted to a specific subject matter area.
The Index is regularly updated. Suggestions or changes to the Index are encouraged and should be directed to the Technology Center (TC) classification contact in the TCs.
The Index is available online to USPTO personnel from the Classification Home Page – USPC Index. The Classification Home Page (http://ptoweb:8081/) is accessible from the desktop via the Patent Examiner’s Toolkit.