Klausner Technologies Inc., the patent holding company of inventor Judah Klausner, said Dec. 3 it filed patent infringement lawsuits against iPhone maker Apple Inc. and the iPhone’s U.S. service provider, AT&T Inc.

Klausner is alleging that the “visual voicemail” feature on the iPhone, which lets users see a list of voice messages and then choose which they want to hear, infringes on two patents it holds. Klausner filed suit against AT&T for selling the iPhone, along with the “visual voicemail” feature and other visual voice messaging services.