So the part that's likely to get fried by excessive current is the isolating transformer, if mains is applied across either of the RX/TX pairs. If it's applied between one RX and one TX, then unless the insulation breaks down there is unlikely to be any current flow - and the isolation transformers are rated to 1.5kV as per the spec, so 120V or 240V won't do it. The 2kV cap for the TX ground reference also stops any current from flowing that way.
I wonder if there's market for NICs with fuses or other protective circuitry on the inputs...
http://www.micro-examples.com/pics/094-EP2-ETHERNET-schemati...
So the part that's likely to get fried by excessive current is the isolating transformer, if mains is applied across either of the RX/TX pairs. If it's applied between one RX and one TX, then unless the insulation breaks down there is unlikely to be any current flow - and the isolation transformers are rated to 1.5kV as per the spec, so 120V or 240V won't do it. The 2kV cap for the TX ground reference also stops any current from flowing that way.
I wonder if there's market for NICs with fuses or other protective circuitry on the inputs...