I wrote some code, and now the our panel switch from 1923 is officially a PC peripheral. 

Github for my test code: https://github.com/theautumn/sender
Github for the DAHDI code: https://github.com/connectionsmuseum/dahdi-linux/tree/revertivepulse

00:00 Intro
2:52 The Problem
3:29 Revertive pulse signaling overview
6:21 The D4 bank & the Computer
9:31 Code overview
15:42 First time it worked!
16:50 Problems and Testing
19:30 Demo!
20:17 Outtro