A group of nine smartphone makers, equipment firms and chipmakers lobbied Congress to free up additional frequencies for wireless use beyond the TV spectrum auction that federal regulators are preparing. In a letter sent to key lawmakers Tuesday, the companies, which included Apple, Intel, Samsung Electronics and Cisco Systems, called on Congress to free up spectrum controlled by federal agencies. "As technology companies, we joined this debate because policymakers need to know that we cannot simply engineer our way out of this problem," the letter said.