SM suppression focuses its protective philosophy on a "power supply input", but offers nothing to protect against surges appearing between the input of an SM device and "data lines", such as antennae, telephone or LAN connections, or multiple such devices cascaded and linked to the primary devices. This is because they do not divert surge energy to the ground line. Data transmission requires the ground line to be clean in order to be used as a reference point. In this design philosophy, such events are already protected against by the SM device before the power supply. NIST reports that "Sending them