This project went through several iterations and variants. I first built one using WiFi to connect to Hıome Assistant, then one using Ethernet (for which I tried several options). I am currently developing an optional battery backup facility that is monitored by Home Assistant.
For details see the Wiki
This project does not include the use of existing 994x keypads as that requires a proprietary serial data interface protocol for which no documentation is available. I have a separate project to reverse-engineer that protocol and connect one or more keyboards to the same ort a separate ESP32 -- see project KELLY.
If you find the ideas in this repository useful, please Buy Me a Coffee