This is a widely used circuit for level-shifting I2C signals that will be familiar to many of us here:
Can it be used for shifting UART signals at, say 9600 baud as well? The simulator doesn't see any problems with that idea. Obviously, UART is not a bus topology, but if you isolated this as a circuit between two devices and used one for RX and one for TX would you foresee any problems in doing that?
I recognize that the pull-up resistors don't serve a purpose in a UART context either (because it's a push-pull driver). But I'm thinking about sharing this level shifting circuit electrically in a context where I might be switching back and forth between open-collector and push-pull drivers (UART / I2C).