One concern system designers may have is increased EMI and reduced electromagnetic compatibility (or EMC) when seeing data transformer-based solutions. Rest assured that preventive techniques have been used to ensure EMI is minimized when using any of Linear Technology's transformer-based PSE controllers. The blue line in the graph on this slide shows the GTEM radiated emissions scan for the DC1840 12-port LTC4270/LTC4271 demo board. Even with its transformer-based nature, the demo board is safely below the CISPR 22 class B limit, represented by the red line, with margin to spare. CISPR 22 has been used globally for many years to determine compliance of IT equipment within applicable limits and is similar to the international EN55022 standard.