Ok, I got everything working! A few notes:
Power
The "Farralon Ethermac SCSI" slash "DaynaPORT SCSI Link/T" takes 12v, center pin positive. I used a Linksys WRT54G power supply and it works perfectly, including having the exact needed barrel power connector.
SCSI
I checked my cable with a multimeter in continuity mode, ensuring that the pin mapping was 1-to-1, and that none of the pins were connected to other pins. Also note that SCSIProbe will show a "No data" indicator, but it doesn't seem to matter.
Drivers
The Farallon driver didn't work for me,
but the DaynaPORT driver did. Installing it is a matter of unpacking the .sit file, and writing the image to a floppy disk using DD in the terminal on modern macOS.
Installing on System 7 is very simple; run the installer. There's a note in the Readme on the disk that says to copy Ethermac to a specific folder... I ignored that.
That driver package seems to support a TON of Dayna products. It did automagically figure out that I needed the DaynaPORT SCSI Link/T driver but I did have the option to select other packages if I wanted to. Very cool!
MacTCP
Of course, you need MacTCP, but as a new user, I found the configuration to be cryptic. I used
macTCP 2.0.6, which gets copied to the Control Panels folder. Here's how I configured it.
- Obtain Address: Manually
- Class: C
- Gateway Address: Whatever your router/gateway IP is
- Domain Name Server Information: The "Domain" column doesn't matter, "IP Address" does, and a default needs to be selected
- Ignore everything under "IP Address" except the class, select Class C if you're on a small home network like me
To specify the actual IP address of your machine, click
Ok to back out to the the first macTCP window, where you can select
Ethernet Built-in and specify your IP address. Click
Close to save the settings.
After you reboot, you're done! I fired up a copy of Fetch and navigated to
Max1zzz's FTP server to test functionality.
I don't think MacTCP supports DHCP but I have not tested this.
Switch Compatibility
I think I've heard some concerns about this adapter not talking to modern switches because it is 5 mbps half-duplex. I've connected it to both a Linksys Workgroup Hub and also directly to my Cisco SG-300-10P, and they both happily have talked to it. The old hub was useful for watching comms with Wireshark from my MacBook Pro.