Power-over-Ethernet based systems are routinely exposed to transient voltage threats. These threats include fast rise-time transients such as electrostatic discharge (ESD) and cable discharge events (CDE).  Additionally, remote powered systems can be subjected to lightning surges. The high peak voltage and current of an electrical transient can easily damage submicron CMOS Ethernet PHYs, and can render an entire electrical system inoperable. This can have significant consequences for a manufacturer, including missed time to market and/or loss of reputation in the industry. Many designers account for protection against common mode transient events while differential mode transient protection is overlooked.