Projects — DEC PR-68 Paper Tape Reader to Parallel Port Interface
I received the PR-68 with the PDP-12, but it didn't have a controller with it. And yet I wanted to read paper tapes. So, I built an interface for the PR-68 to connect it to the parallel port of my PC, and wrote a tiny program to grab data from it, running under QNX Neutrino.
This is the front of the PR68E paper tape reader.
The PR-68 Back
This is the back of the PR68E paper tape reader.
The PR-68 Insides
This is the inside of the PR68E paper tape reader.
This is the final assembly picture showing the PR-68 tape interface box. I built this into a 20 Meg hard drive case that I bought for $5 at a local scrapper. Basically, the circuit consists of a 7474 flip-flop that generates the 4 phase signals, and these are then amplified by the transistors to drive the stepper motor in the PR-68. Two DB-25 connectors (bottom left) connect to the PC's parallel port and the PR-68.