USB CAT and CW Interface for FT-817

Grumpy-CatThis is a simple optical-isolated CAT interface that I’ve built recently to control my QRP rig FT-817 with my laptop, via USB, and also CW keying by software during contests.

The schematic design is very simple and minimal. It contains a cheap USB to serial converter, bought from eBay with less than 2$, a small circuit with three PC-817 optocouplers, RxD/TxD/CW, some current limiting resistors and a bunch of cables and connectors.

CAT & CW Interface Circuit

USB CAT & CW Interface Circuit

All the circuit was built on a small piece of breadboard, 25 x 20 mm, since there was no need to make a PCB for that. The voltage supply for RxD is taken from the USB 5V pin, on the converter.

Cheap eBay USB to SERIAL converter

Cheap eBay USB to SERIAL converter

The male USB and DB-9 sockets were removed from the PCB, so along with the interface breadboard were fitted into a small plastic box, code PP85NC from TME. A scrap USB cable is connecting the interface with the PC, and for the rig, a 4 wires cable with a mini-DIN 8 pins for ACC port and a 3.5 mm jack for CW.

FT-817 CAT & CW  USB Interface

FT-817 CAT & CW USB Interface

This is the interface all wired up. I had tested it with the FT-817ND at 4800 and 9600 baud rate and all was working ok. Although this circuit can work also with FT-857 and 897, I have never try it.

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8 Responses to USB CAT and CW Interface for FT-817

  1. cygnusaerial says:

    Hi, I’m going to build this interface for my FT 817. Can you please tell me about the software setup detail and what is the software I have to use for CW operation?

    • Adrian says:

      Hi, I use it with N1MM. In Config > Configure ports etc there you select at the respective com port number in which your usb serial adapter is installed, you check DTR for CW. Or I believe with any other program that can transmit CW, you try to find the settings for Serial ports and select that CW is transmitted through the DTR pin of the serial port.

  2. Alberto Guersi (EA8AGF) says:

    Hi Adrian, having red your article refering to FT 817 nd and the way or CATing it for CW, I decided to build one right away for mine. May I say I’m very pleased with results. It was very easy to handle and worked at the first attempt. Software was N1MM logger but have to try with different ones.

  3. Adrian says:

    Hi Alberto, usually with most of the software available must work.

  4. HG8-654 says:

    Hi. I built this interface, I have FT-817ND, and a USB To RS232 TTL CH340G Converter Module Adapter STC replace Pl2303 CP2102 Z3 but it wont work. The optocoupler is a PC817… What do you think about problem?
    73&DX! HG8-654

    • Adrian says:

      Hi, your converter is a USB to TTL, mine is a generic USB to serial. I am not so expert in this, but I think the TTL can be connected directly to the CAT of the rig, but please document more about this before trying, as I said I am not 100% sure. Otherwise, get a USB to serial one and should work. 73 Adrian

  5. kk4vcb says:

    I use Ham Radio Deluxe and CWType. These 2 programs do not appear to be able to share a com port. What software did you test with?

    • Adrian says:

      Hi, I use HRD for CAT control and PTT when working digi modes, and is ok. But mainly I use this interface with N1MM when contesting in CW, for CAT and CW sending.

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