Sprint Nextel on Monday sued Comcast, Time Warner Cable, Cox Communications and Cable One, alleging that the cable companies infringe 12 patents related to transmitting voice calls over Internet Protocol networks.
The cable operators declined to comment on the Sprint lawsuits. The suits were reported Monday by Bloomberg.
Separately, within the last three weeks, Comcast, Time Warner Cable and Cox have each entered into deals with Verizon Wireless -- a major Sprint competitor -- under which the MSOs will resell Verizon Wireless's products and services and the cable operators agreed to sell Advanced Wireless Services spectrum licenses to the carrier.
Sprint filed four separate lawsuits against the MSOs in the U.S. District Court for the District of Kansas in Kansas City.
"The cable companies sued by Sprint are continuing to offer phone services that use this technology without obtaining a license or permission from Sprint," the wireless company said in a statement. "Sprint alleges that each of these companies has infringed at least 12 [voice-over-IP] patents by selling cable voice systems and services that use the technology protected by the Sprint patents."
The dozen patents at issue include some that Sprint had successfully sued voice-over-Internet provider Vonage over, according to Bloomberg. A federal jury in September 2007 found Vonage infringed six Sprint patents, after which Vonage agreed to pay $80 million to Sprint to settle the lawsuit and to license Sprint's VoIP patent portfolio.
Over the last several years, Sprint has been a strategic partner to major cable operators.
Comcast and Time Warner Cable (along with Bright House Networks) hold equity stakes in Clearwire, the mobile broadband provider that is majority-owned by Sprint. The MSOs had been reselling Clearwire's 4G WiMax service, but that arrangement is ending within the next six months under the exclusive deal with Verizon Wireless.
In addition, Comcast, TWC, Cox and Bright House joined with Sprint in the Pivot joint venture, under which the cable operators attempted to sell 3G voice and data services provided by the wireless carrier. That partnership ended in 2008, less than three years after its formation.
Sprint also has provided VoIP and interconnection services to MSOs including Time Warner Cable. Last year TWC announced it would phase out its use of Sprint's services over the next several years.