Apple introduced a new version of the Macintosh II NuBus Ethernet Card in
December 1990, replacing the old version. Both boards have the same part
number: M0410LL/A.
What is the difference between the two cards?
Whenever Apple Manufacturing changes a board layout or card design these
are considered "revisions". In the case of the December 1990 revision, it
was a board layout change. There were no changes to functionality or power
requirements.