IDT, the Newark telecommuni cations company, yesterday posted a narrower second-quarter loss, as its core prepaid calling business was hurt because of what executives said were unfair business practices by competitors.

For the quarter, IDT shaved its net loss to $27 million, or 33 cents a share, compared with $55.6 million, or 58 cents a share, in the same quarter a year ago. The results were far short of Wall Street's ex pectations, as analysts had ex pected the company to post a loss of 17 cents per share.

Revenue also declined significantly, dropping nearly 10 percent, to $512.5 million, as the number of minutes in its core prepaid calling card business fell dramatically despite price cuts made by the company.

The drop in minutes led IDT to investigate its competitors' calling cards, a probe that they said discovered their rivals significantly overstating the number of minutes delivered by those cards. As a re sult, IDT filed a civil anti-fraud lawsuit against more than a dozen competitors in U.S. federal court in Newark, seeking a preliminary and permanent injunction against the rivals.

In the complaint, IDT charged the defendants' actions have hurt the company's market share, caus ing a drop in revenue as well as net income. The complaint alleges the deceptive practices by the competitors are causing consumers to lose more than $1 million a day.

"We are convinced that unfair labor business practices by competitors have created an unlevel playing field," IDT Chief Executive Jim Courter said in a conference call with analysts. "We are simply unable to compete in a market where customers are told they have 90 minutes remaining on their card when they don't."

IDT was committed to doing whatever it needed to return its core calling card business to its "profitable and dominant position," Courter said, but added "success will take many months."

During the quarter revenue for prepaid products fell to $241.9 million, from $303.4 million in 2006, and its loss grew to $13.9 million, from $2.6 million in the year ago quarter. Executives said it is entirely possible IDT will never regain the revenue it has lost due to the alleged unfair business practices.

The defendants in the lawsuit number 13 companies, including Dollar Phone Enterprises, a Brooklyn company; Epana Networks, a New York company; and Locus Telecommunications, based in Englewood Cliffs.