The new boards with protection diodes have arrived. After a quick soldering, we had a beautiful proto on our desk. https://www.flickr.com/photos/helsinkihacklab/17377299853/in/dateposted-public/
We tested the boards, full 100MBit/s speed was reached. The next test was to see if our clamping diodes work as they should, so it was oscilloscope o’clock.
The protection diode clamps the voltage spike to roughly 9 volts. Next thing to do was to plug the cable in and out ~100 times and see if the board would still connect. And connect it does! Now all that remains is to do a few cosmetic adjustments and launch the campaign.