Thanks for any pointers!
What were you hoping to connect? Macs don't have serial ports.
Phil, although most contemporary Macs don't have exposed UARTs, I'm more interested in updating an older chunk of FPC code that used the serial unit on the Mac.
The Mac's darwin kernel has a serial library like most Unix-like systems and I can happily write C, Lua, Python, etc code that accesses these functions to access a serial port connected via USB.
Having said that, can you offer any useful suggestions on where the serial unit may have gone in later releases of FPC for macOS?