The IC-746 driver is a bit of an oddball insofar as it's the only one of the Icom CI-V drivers that doesn't appear to define its own memory format. Whether that's because it was the first of these drivers, and therefore got to define the core classes, I don't know.

Nope, it was actually the third (after the 7200 and then the 7000)! FWIW, I think it _does_ actually have its own frame format, it just calls it "DupToneFrame" because it was like the earlier ones, but.. had duplex/tone which the 7200 doesn't. I think that at that point we were probably thinking that the memory format would be more consistent among models. Nothing else actually uses that except the 746, if I'm reading correctly.

As such, though, it's perhaps not the best place to start. Following the design of the IC-910 driver is likely a better bet, though you'll probably want to look at others for tips on what the format might look like. Given that I've seen the IC-746Pro referred to as the IC-7400, it's possible that you may get tips from looking at the IC-7300 format. I wrote the IC-910 driver, and am happy to help with questions.

Perhaps just one reason to look at the 746 instead is that it's very bare-bones and the 910 has a lot more features and the 23cm probing thing. But yeah, fair point that starting with (or at least consulting) one that has gotten much more love over the years is probably a good idea.

--Dan