What do FT817, FT857 and FT897 have in common? The documented CAT protocol, for remote control of some functions of the radio.
What have I been mostly writing about in the past 2 years? CAT protocol :-)
In a mail exchange about my 817 accessories, a builder asked me if there is a way to emulate the CAT protocol on the PC. It is possible, probably with little effort, but I am not able to do it. But I can easily do it on an microcontroller system: it is a matter of "reversing" the code for my FT817 keypad, so that it will respond to commands.
I had never though of it, but a CAT emulator allows to test my accessories without having the FT817 around. That's why I am going to write the code.
This device can be as simple as an ATtiny2313, XTAL, 2x27pF. A LED could blink on data transfer, no LCD needed. Software-wise it will ignore unknown commands and initially keep the VFO frequency and mode set by the controlling device. More functions to be added if/as needed.