I used to be a patient man...sigh.
This project was also 10 years ago but for university.
The LED matrix was mounted on top of the circuit board in a "shield like manner" and Wire wrapped to each other.... you read that right, yes, Wire Wrap.
There was a DB-9 pig tail not shown here out of each circuit board to connect it to a PC terminal and another to daisy chain further boards.
it displayed the incoming chars and forwarded the old one to the next module if any.
Enjoy this project?