I love this article, but I just can't help but pick at this nit I have with the "charging the capacitors" part. I'm not intimately familiar with Ethernet specifically, but I am an electrical engineer. Since the voltage on a capacitor is directly related to the charge it has stored ( scaled by a factor called it's capacitance :-) ), holding the capacitors at any fixed voltage for any length of time does not change how "charged up" it is at all. I would believe that there is a "line balancing" goal to the transmissions, but I'd be willing to bet it is to avoid driving the isolation transformers into saturation, and has nothing to do with low pass filter capacitors...