We've been designing all sorts of IR transmitters and receivers for the Adafruit shop lately, and a chance discussion got us thinking about IrDA - an old wireless protocol used in some PDAs, watches, laptops and toys. its not used anymore - bluetooth LE does a way better job - but there's probably some cases where IrDA hacking could be useful such as communicating with retro devices or if you want an RF-less wireless link. here's a board that combines a TFBS4711 transceiver (https://www.digikey.com/short/jn43cz31) with a MCP2112 codec (https://www.digikey.com/short/m8tp3708). you can communicate at 115.2kbps with RX and TX lines just like any UART. 115.2kbps is the standard baudrate. or, provide your own CLK for something like 9600 baud.