At long last, photos of some early ether (2.94Mbit).

The way the story was retold, the researchers at PARC couldn't figure out how to tap the coax cable with the right impedences (they didn't want to have to cut the cable). One of the researchers suggested looking at a cable parts catalog and they came up with using the vampire taps you can see in the photo.

BTW - Metcalfe prefers calling it 2.94Mbit Ether rather than 3Mbit ether because the rounding error is greater than the speed of ARPANet at the time (if I got my facts right).