FT8x7 CAT Emulator: success

As announced few days ago, I have developed a simple and cheap hardware that emulates the CAT interface of ACC port of a FT-817/FT-857/FT-897 transceiver.

This is useful for testing devices without having a real FT-8x7 at hand. A short circuit on the accessory will not damage radio internals. A software bug will not keep your radio on hold or ruin its settings while you are busy developing or testing your solution.

The FT-8x7 CAT Emulator is based on a Atmel ATtiny2313 microcontroller (the same of my FT-817 keypad) and it accepts all standard documented CAT commands at 9600 baud. Feed it with 12V and the Emulator will power your accessory too, as if it were a real FT-8x7 transceiver.

A LED blinks when a 5-byte sequence is received at the emulator side.

Schematic diagram for IK1ZYW FT-8x7 CAT Emulator

The emulator handles two VFOs with frequency and mode and the get RX/TX status commands. Other Yaesu officially documented commands have been implemented but do not return data to the CAT accessory, so their usefulness is currently limited.

At powerup the Emulator initializes its internal VFO representations on 14200 USB and on 145500 FM. You may QSY using your accessory (keypad, FR, IFR, computer control software, ...) and the new value will be kept until power off. Since this is a tool meant for testing devices, it always powers up in a known VFO state (14200 USB and 145500 FM).

RX and TX status are returned with a static string, just to give some valid data to the CAT accessory to play with.



Conclusion. This is a blind emulator of the FT-8x7 standard CAT protocol. It feels like hiding your transceiver in a black box and controlling it with an external accessory. But it is indeed useful for testing all sort of CAT devices without having an FT-8x7 at hand. Firmware for ATtiny2313 will be available through my pages soon (the impatient can send me an email request).