Today's coding fun was all about adding CAT functionality, so that JTDX, WSPR-X, and so on can all interact with the transmitter just like a real rig. After a bit of choosing I settled on emulating the Yaesu FT-450. The CAT commands are well-documented, though debugging without any way to see what was passing over the serial port was a bit of a git. Got there in the end.
So now the transmitter jumps frequencies whenever you change bands in whatever software you're using - sweet. Or I can manually change frequency by sending an ASCII string like "FA14074000;"