The chip used in this monitor is CD1379CP for those that are interested.
https://pdf1.alldatasheet.com/datash.../CD1379CP.html
Not a bad monitor for about $9 shipped on ebay. Happened to be searching just the right terms at just the right time. There was no brand info on the doorbell, so I couldn't tell you a model to search for. It is not an Aiphone. Removing it from the door intercom base was simple and the display is a module with just a few wires going to the mainboard that were labeled even.
Now I am playing around with filters to put on the glass to color it red or green for effect and more sharpness. I will probably have to modify it to increase the brightness a little more.