Rates Technology Inc., which holds patents for the process by which most Internet phone calls are made, confirmed Friday that it is suing Google Inc. (GOOG) over its Web-based phone calling system.

New York-based RTI said it estimated that damages from the lawsuit could reach $5 billion, assuming the litigation process takes four years as the market for Internet-based phone services booms.

"Ordinarily we don't need to sue people to get them covered under our patents," RTI President Jerry Weinberger told Reuters. "Every once in a while we run into utter arrogance."

RTI holds two patents in the telecommunications field and generally takes a one-time fee of up to $5 million to cover companies who provide the services or the equipment to support them. It filed the suit against Google in October.

Weinberger said companies covered under RTI patents include Yahoo Inc. (YHOO), Microsoft Corp. (MSFT) and Verizon Communications (VZ).

RTI is currently holding talks with Time Warner Inc. (TWX) about its Internet unit AOL and with online auction site eBay for its Skype voice offering. RTI is also locked in lawsuits with Cablevision for its cable voice service and with broadband phone service company Vonage.

Google confirmed it would add instant messaging and Web-based phone calling, known as Google Talk, to a growing menu of services it has added to its core Web search functions.

Google officials were not immediately available to comment. Company shares fell $4.75 to $415.40.