US telecoms group AT&T has accused Google of benefiting from an unfair competitive advantage by ducking federal communication rules.
This is enabling Google to block calls to rural areas to save access costs, which competitors bound by a 2007 Federal Communication Commission (FCC) ruling are prohibited from doing.
AT&T has set out its objections to Google's practices in a in a strongly worded letter to the FCC's competition bureau, accusing Google of openly flaunting the call blocking prohibition.
The telecoms group has called on the FCC to ensure that any new rules are applied not just to network operators but also providers of internet applications, content and services.
Anything less would be ineffective, legally suspect and, in all events, a direct repudiation of US President Obama's call for a 'level playing field,' said Robert Quinn, a senior vice president at AT&T.
Google has admitted to the blocking practice, but insists that Google Voice is a free, Web-based software application, which means it is not subject to common carrier laws.
Users of Google Voice are still able to make outbound calls on any other phone device, he said.
" AT&T is trying to make this about Google's support for an open Internet, but the comparison just doesn't fly," Whitt wrote.
The FCC's open Internet principles apply only to the behavior of broadband carriers, not the creators of Web-based software applications, he said.
Whitt accused AT&T of trying to use the regulatory process to undermine Web-based competition and innovation.