I missed this one before, when it was announced at Electronica: the Uno SPE Shield, created by Arduino and Microchip working together. It turns out, though, that it wasn't available back then. And it ...

Arduino UNO SPE Shield adds Single Pair Ethernet (SPE) and RS485 to Arduino UNO and compatible boards, notably the Arduino UNO R4, via a Microchip LAN8651 SPE controller. Single Pair Ethernet relies ...