SJ Research Nexus interface for A3000 (top)
SJ Research Nexus interface for A3000 (back)
Nexus is a proprietory network solution produced by SJ Research, this card in an interface for A3000s (and no doubt also works for A3010, A3020 and A4000). NB This is not an Ethernet interface!
The PCB says PCB 1035 Issue 6. The card's serial number is A-51650. The ROM is Client V0.27