After less than a month as a standalone company, Embarq filed suit this week against AT&T in a dispute over network access fees.

Spun off from Sprint Nextel in May, the local wireline carrier claimed it is owed millions of dollars for terminating long-distance calls for AT&T.

AT&T has avoided paying intrastate fees in 13 states on calls made using certain prepaid calling cards, Embarq alleged. Since 2002, Embarq said, AT&T has been calculating its termination fees by counting each intrastate call as two less expensive calls: one from the caller to an out-of-state switch, and one from that switch to the recipient, back in the state where the call originated.

Embarq further claims AT&T has been warned against using such calculation methods by the Federal Communications Commission.

AT&T has not yet publicly commented on the lawsuit, which was filed Wednesday in a U.S. District Court in Kansas City.