Title: Accessories providing a telephone conference application one or more capabilities independent of the teleconference application
Type: issued patent
Patent number: 7,167,897
Issue date: January 23, 2007
Filing date: May 8, 1996 (No, that is not a typo. This case was pending a long time. The term extension is 875 days (about 2 years and 5 months).)
Link to PDF: 
AIPW Summary: This patent relates to a teleconferencing application. The application has a base component which is usable by most computers. Additional features (such as file transfer, etc.) can be used at any station participating in the teleconference, and their use is separate from the teleconference application and can be invoked without affecting the teleconference.
Side note: This case is old enough that the specification (at column 5, lines 3-16) refers to a Mac 8100 (March 1994 – July 1995; see Apple-History.com for more info) and a Symantec C++ compiler (which, best I can tell, hasn’t been around since 1997 or so).