This is a stealth project I've been slowly working through for some time now. With Comm Slot II Ethernet cards being hard to come by, and often for high prices, it seemed like a decent target for recreation / re-engineering.
My approach here was originally going to be "remake the official Apple card" until I discovered that Farallon had made a 10/100 card. That sent me on somewhat of a research trip, digging into Ethernet hardware and compatibility for several weeks until I discovered a single-chip solution for 10/100 exists with wide Mac OS compatibility. The identity of this chip will not be revealed at the present time to ensure I can acquire a sufficient quantity of them.
Having found a compatible chip, I ordered a PCI version of it and reverse engineered it with help from the chip's datasheet. Because in case people didn't know, Comm Slot II is PCI with fewer pins. Only one interrupt pin is available instead of four, there aren't the 64-bit transfer controls, things like that.
Quite interestingly, despite being a 10/100 capable chip I'm only seeing about 150k per second max download speed (from Macintosh Garden) with the original PCI card installed in my G3 7300. There must be some degree of OS-side and extension-level driver handling which limits transfer speeds. But the hardware is capable of a 100 megabit link which should help compatibility with newer networking hardware that often doesn't like "plain 10".
The Comm Slot II card reaches speeds of around 70 to 90k per second download on my 6400. It's not exactly a speed demon and I'm wondering whether anyone else has experience with CS II Ethernet cards to compare speeds. Maybe pulling files from a local FTP would be faster, haven't tested that yet.
I can hear you clamoring for a picture, so fine. Chip numbers are redacted for reasons mentioned above.
My approach here was originally going to be "remake the official Apple card" until I discovered that Farallon had made a 10/100 card. That sent me on somewhat of a research trip, digging into Ethernet hardware and compatibility for several weeks until I discovered a single-chip solution for 10/100 exists with wide Mac OS compatibility. The identity of this chip will not be revealed at the present time to ensure I can acquire a sufficient quantity of them.
Having found a compatible chip, I ordered a PCI version of it and reverse engineered it with help from the chip's datasheet. Because in case people didn't know, Comm Slot II is PCI with fewer pins. Only one interrupt pin is available instead of four, there aren't the 64-bit transfer controls, things like that.
Quite interestingly, despite being a 10/100 capable chip I'm only seeing about 150k per second max download speed (from Macintosh Garden) with the original PCI card installed in my G3 7300. There must be some degree of OS-side and extension-level driver handling which limits transfer speeds. But the hardware is capable of a 100 megabit link which should help compatibility with newer networking hardware that often doesn't like "plain 10".
The Comm Slot II card reaches speeds of around 70 to 90k per second download on my 6400. It's not exactly a speed demon and I'm wondering whether anyone else has experience with CS II Ethernet cards to compare speeds. Maybe pulling files from a local FTP would be faster, haven't tested that yet.
I can hear you clamoring for a picture, so fine. Chip numbers are redacted for reasons mentioned above.
Not to mention opening your design to the well heeled TAM crowd, length of the standard CSII form factor is the only thing standing in the way of using that slot sans riser in the TAM. 
