The FCC recently sent companies like Google, Microsoft and Earthlink back to their labs after their initial white space devices did not meet the commission’s approval. White space devices are second class of devices meant to operate in the 700 MHz spectrum. These devices are not meant for use in the spectrum cleared by TV stations for next year’s auction. Instead white space devices operate in unused bands still dedicated to TV signals. These empty spaces very from city to city, so devices have to find an empty band where they won’t interfere with TV signals. The first devices submitted to the FCC were not able to work without causing interference, forcing the FCC to hold off on approving the technology.