Calling into question recent test findings that a model wireless device designed for use in digital television (DTV) “white space” channels would interfere with TV broadcast operations, Microsoft told the FCC on Monday that its prototype had simply malfunctioned and that a duplicate device later demonstrated for officials of the FCC’s Office of Engineering and Technology (OET) worked properly. By October, the FCC is expected to rule on the operation of unlicensed mobile devices within unused TV white space bands at the end of the DTV transition. As part of a coalition of technology and Internet firms that include Google, Intel, and Dell, Microsoft produced a device that would operate in white space spectrum to provide wireless Internet and data services on an unlicensed basis to residential and business users. In a development that is expected to contribute heavily to the FCC’s decision, however, the OET issued a laboratory report last month indicating that the Microsoft prototype and a second device produced by the U.S. subsidiary of Dutch equipment giant Philips failed to detect adjacent DTV signals reliably or caused interference to DTV operations. In documents filed with the FCC, Microsoft asserted that the OET’s “aberrant test results” were attributable to a damaged scanner within the device provided originally to the agency. According to Microsoft, a duplicate prototype device “reliably detected occupied television channels” during a demonstration conducted before FCC officials last week. The company urged the FCC to revisit the OET’s findings. Backing the OET’s original findings, the National Association of Broadcasters (NAB) charged that Microsoft’s “selfserving agenda” may jeopardize “America’s access to interference-free television reception.” Observing that “the entire over-the-air digital broadcast system and derailment of the DTV transition is all based on whether a specific device works in a lab,” a spokesman for the Association of Maximum Service TV quipped: “imagine the disaster if millions of these devices enter the market and they start to break.”