CCSO (often shortened to CSO) is another search tool found at many universities and large organizations. CCSO stands for Computing and Communications Services Office at the University of Illinois, Urbana- Champaign, which is where the directory and search tool was developed.
CSO allows the user to search for a person's name, e-mail address, department, etc. The CSO directory will return any information available for the person or department, and often includes phone numbers and e-mail addresses.