As Google Voice launches across the US, a Connecticut firm is accusing Google of violating one of its patents with the new service.
Frontier Communications is seeking unspecified damages and an injunction to prevent Google from using the enhanced telephone services technology.
"Google's deliberate infringement of the [patent] has greatly and irreparably damaged Frontier," reads the complaint filed in the Delaware District Court.
The patent relates to a pretty central feature of Google Voice - the ability to use a single contact number for all their landlines, cellphones and other devices. It describes how a user can be "reached on multiple telephone lines from a single dial-in number."
The suit comes just as Google launches the service across the US - up to now, users have needed to be formally invited.
"Today, after lots of testing and tweaking, we’re excited to open up Google Voice to the public, no invitation required," say Craig Walker & Vincent Paquet, Google voice product managers, on the company blog.
The service includes features such as voicemail text transcriptions which can be delivered as texts or emails, free outbound domestic calls, cheap international calls and free conferencing.
Google plans to defend the Frontier lawsuit. Given that it acquired the technology three years ago when it bought GrandCentral - and GrandCentral launched in 2005 - Frontier may have to be very persuasive.
It's not the first time Google Voice has caused controversy. AT&T complained last year that the company was violating net neutrality rules, prompting the FCC to investigate.