We have a winner! Actually I remember those. Whenever you got garbage characters mixed in with the text you knew it was time to cram another rag in between the receiver and the rubber recepticle in order to damp down the acoustic signal.
If you wanted to play Duke Nukem on-line, someone had to laboriously draw out each frame of the action using ASCII characters and then transmit them to every player at about one frame every four hours. That's how I remember it, anyway.
---
I was gonna send a robot back in time, but I got high.