An old US Robotics patent from the early 90's is the basis for a new patent lawsuit against most of the big VoIP gateway vendors. MetaSwitch, Sonus, Cisco, and Audiocodes are among the targets. You can get the court filings (for free) and my informal IANAL technical analysis of the case: http://www.200ok.info/2009/09/ianal-analysis-of-patent-5912888-claims.html I am not a lawyer. mark r lindsey at e-c-group.com http://e-c-group.com/~lindsey +12293160013