Ethernet interface must first be categorized for their port type, which depends upon the specific application connections. Generally, Ethernet interfaces may be characterized as a Port Type 3b/5b, even though they may be characterized as Port Type 3 or 2, 3A/5A, 4 or 4A. This characterization is the first step that must be fully determined so that the correct resistibility levels are known. If the port is classified as a Port Type 3b/5b, this table shows the lightning surge testing requirements. Surge one, at the user’s discretion, can be either an ±800V (open circuit generator value), with a 100A short circuit capability (fictive impedance of 8 Ohms) based on the double exponential 2/10µS waveform (2µS rise time to peak, 10µS decay from origin to half value) OR a ±800V, 100A short circuit test based on the combination 1.2/50-8/20µS (voltage waveform is 1.2µS rise time to peak, 50µS decay from origin to half value and a current waveform of 8µS rise time to peak, 20µS decay time to half value as measured from the origin). This test is conducting alternate polarities five times for each polarity time. The unit under test must continue to function after each and every test application without requiring any human intervention (no user reset is allowed). Test condition 2 is then either a 2/10µS, ±1500V, 100A generator setup OR an 1.2/50-8/20µS, ±1500V, 100A generator setup for ±5 times. Test condition 3 is showing a test condition level that is determined by the turn on level of the protection. i.e. the exact same test generator as selected for the previous two test but with the open circuit voltage set to the maximum voltage level that does not activate the over-voltage protection components. A 1000 Base-T interface uses eight individual wires (four wire pairs), therefore the testing levels are slightly lower for each individual wire taking into consideration the dividing effect with additional wires in the bundle. The 1000 Base-T interface is tested ONLY with the 1.2/50-8/20µS generator but with additional series resistance in the setup to limit the short-circuit current (if the generator was surged into a load with zero impedance) to the values listed in the table. The 1000 Base-T 4 wire pair example surge condition is limited to a short circuit value of 36.4A per wire with an open circuit voltage of ±800V repeated five times for each polarity. The A1, A2, A3, and A4 testing is differential (also known as metallic or transverse) testing. The B connection is a simultaneous common mode test on all wires.