The US International Trade Commission is going to investigate allegations by Microsoft of patent infringement by the French telecoms equipment maker Alcatel-Lucent.
The ITC said it will look into alleged infringement involving technology Alcatel imported into the US that "integrates the features of data networks and traditional telephone networks," according to an ITC statement.
Microsoft, which filed the complaint on 16 February, asks the ITC to exclude the disputed products from the US market and issue a cease and desist order against Alcatel-Lucent.
The tables were reversed last month when Alcatel-Lucent won a $1.5bn jury verdict in a San Diego, California, court against Microsoft for infringement on an Alcatel-Lucent patent for MP3 technology used to play music files. Microsoft is appealing that decision.
In yet another case, a San Diego federal judge dismissed an Alcatel-Lucent patent infringement claim against Microsoft on 1 March over speech-recognition technology.
The latest probe will be referred to an administrative law judge, Paul Luckern, who will schedule hearings.