3Com Etherlink III is one of the most popular network cards for retro PCs.

It has a lot of versions and almost all of them work very well.

Some cards have a place for a ROM chip that can be used, for example, to load an XT-IDE BIOS (tested).

See also:

• 3Com 3c509 on Wikipedia
• 3C509 tools on RetroCmp.de

I use one of these network cards on the Toshiba T3200SXC 386-class portable computer.

Etherlink III card with EPROM inserted.