Ah, yes. But a roll- your own device with C++ on bare metal, so lots more fun.

(we’ll need a few thousand of these, and the off the shelf solution is around 1k vs $1.50 for RYO )

By the way, the RISC V espressif esp32-C3 is a really amazing device for < $1. It’s actually cheaper to go modbus-tcp over WiFi then to actually put RS485 on the board like with a MAX485 and the associated components. Also does ZIGBEE and BT, and the espressif libraries for the radio stack are pretty good.

Color me favorably impressed with this platform.