Keven, I just came upon your email. What a fantastic project!!! Did you chronicle your learning and struggles? I am VERY interested since I am the Curator of the IH Museum, and a WE/AT&T/LU/ALU/Nokia/TTY/etc. fanatic!
I also have ported the AT&T 730 terminal tools from the 3B2 to modern Debian Linux and the Raspberry Pi Zero W ($10 computer), and got visdn working on AT&T 7506 ISDN phones and the 730 with ISDN simulator to I can call between phones using visdn on the 730!
I am also restoring/refurbihing a Teletype Model 43 printing terminal.
I also have a 3B2 400 or 500 that I need to get working (after sustaining water damage decades ago).
So I'm very interested in your project.
Chuck Rehor
chuck.r...@nokia.com