Neither of the cables are suitable for the Etherlink III.
What you need:
The RJ45 cable (please note, there are 10M only and 10/100M cables! not interchangeable, you need the 10M only kind, you can tell by the amount of LEDs and the 100M text in the 100M cable)
or
The RJ45 + BNC balun
These adaptors are NOT interchangeable between different brands of pcmcia cards, you need to have adaptors that are meant for the type of card you want to use.
Even though the connector on the edge of the card is the same, the pinout / electrical characteristics are not.
At least the 3c589 is very common, so you can find those adaptors easily. Don't know about the Zonet one.