Hello,

I would like to share my project that is long overdue for publishing here - MacTwister, a fairly universal Twisted Pair breakout board for a variety of SE and SE/30 network cards. It's about the small PCB that you screw to the computer chassis that contains an external connector.

I was motivated to complete this design as I had one "widowed" MacCon without a connector board and my other MacCon and Etherport only had coax+AUI connectors and would require a not so nice external converter.

Here comes MacTwister:



So what's the deal? First of all, the idea is to support two typical connection pinouts for the common network cards:

• Asante MacCon (both SE and SE/30 tested)
• Shiva/Kinetics EtherportSE (tested) and Dayna (not tested, but it seems it has the same pinout)

The card can work with both network cards without any modifications, you just need to plug the 16pin IDC cable into the correct socket. This card is not a network card, it requires one of the above mentioned cards to be present.

But "there is one more thing". Because of the short supply of AUI↔Twisted Pair transceivers, the card was designed to support all three common options from the era:

• T7220 (and T7220A which is backwards compatible)
• AM79C98 (DIP case)
• LXT902PC (PLCC case)

I managed to find all three types on ebay/aliexpress and test them. Below you can see 3 cards with different transceivers, all working without electrical changes (minus the three jumpers that need to be bridged for LED indicators to work with AM79C98).


My SE and SE/30 are happily running with the breakout board!


You can find more details about the project here: https://dymczyk.com/mactwister-maccondaynaetherport-rj45-breakout

Finally, action items:
1. I'm looking for 2-3 early testers of the card - I could supply the newest version and I would be happy to get feedback, particularly a heads-up if it works. Please let me know!
2. I have a few (around 10) spare cards of the newest revision which are mostly populated, but I would need to order a few components to finish them. Please drop me a message or post here if you would be interested in the card at about $35/CHF35 + shipping. I can then post in the Trading forum with the details, but I would like to gauge the interest.

This is amazing! Excellent work, sticking the thread!

Since the web site has disappeared I assume this project never came to fruition. A bit sad because I could use one.