AT&T, Verizon and CenturyLink embroiled in ADSL patent fight with Brandywine

January 3, 2013 | By Sean Buckley

AT&T (NYSE: T), Verizon (NYSE: VZ) and CenturyLink (NYSE: CTL)--three of the largest U.S. incumbent telcos--are in the midst of a patent war with Brandywine Communications Technologies, a patent holding company.

In a number of U.S. court complaints, Brandywine claims that a number of telcos and CLECs have infringed on seven different DSL-related patents that it says it owns.

At issue are patents that relate to various DSL-related techniques, from "detecting loss of echo cancellation" (U.S. patent number 5,206,854) to "predistortion technique for communications systems" (U.S. patent number 5,251,328).

To date, Brandywine has sued over 39 different service providers.

In addition to filing a lawsuit against AT&T, Verizon and Centurylink last year, the company has sued Windstream (Nasdaq: WIN), IKANO, and Megapath. It is also currently trying to settle one of its cases with EarthLink (Nasdaq: ELNK).

Brandywine's moves are familiar to anyone who's been following the string of patent infringement claims--some apparently legitimate, others somewhat sketchy--that have plagued providers across the industry.

Last May, a group of eight service providers and vendors, including Alcatel-Lucent (NYSE: ALU), EarthLink (Nasdaq: ELNK), and Metro PCS, entered into separate patent agreements with visual voicemail provider Klausner Technologies for its consumer and enterprise visual voicemail products. 

However, three of the other 12 defendants, including Toshiba America, Primus Telecommunications, and Paetec--which at that time had just been acquired by Windstream, now also defending a patent infringement lawsuit brought by Klausner, did not settle.

While Brandywine is the latest so-called "patent troll" to emerge, they likely won't be the last as patent disputes have been an ongoing issue in both the wireline and wireless segments of the telecom industry. A recent report found that patent infringement lawsuits have increased over the past five years from 22 percent of all patent lawsuits filed to 40 percent.