PTT not working for Yaesu FT-65 or FT-4X - not a DigiRig problem or DigiRig cable problem

Interesting. Is your FT-65 one of the ones made in China or the later ones that were made in Japan? Mine was made in Japan and both my FT-4 and my FT-65 fail to detect the state change.
I see the change in state on the output ring of the Digirig FT-65 cable when I “TEST PTT” or “TUNE” in WSJT-X. Also, shorting the sleeve to the ring on the 4 pole Digirig cable end doesn’t cause PTT, but I opened the case of the external microphone and I am able to short the two wires on the mike cable and it goes into transmit, which leads me to believe there’s just something about the cable.
But, I ordered a two pole cable with tinned ends to test and see if it works.
Thank you for the information.
Steve - AI7KS

My FT-65R is pretty new and made in Japan. I agree it sounds like an issue with the plug to HT connection, or possibly the cable isn’t pulling to ground as hard as it’s supposed to?

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Well, although my experiment had to be truncated, I did have some promising results.
I ordered a four pole plug with a breakout terminal on the other end. I also ordered a two pole 3.5 mm plug with tinned ends and a two pole 2.5 mm plug with tinned ends.
I’ve inserted the tinned ends into the terminal block to match most of the DigiRig connections in the diagram posted by Denis above.
The success I had is that with this configuration I am able to short across two of the connections and see the FT-65 reliably transmit.
I have one more connection to make and I have to insert the 2k resistor in the PTT line (I’m connected directly right now). Then I’ll test it again.

I finished the experiment. I added a 2k resistor in-line between R2 on the four pole end and the tip of the 2.5 mm two pole plug that goes into the mike input of the FT-65 or FT-4.
Also R1 on the four pole plug is connected directly to the tip of the 2.5 mm two pole plug.
Shorting the sleeve to R2 on the four pole plug now puts the radio into transmit on both radios, which didn’t work for either radio before using the three pole plug of the genuine Digirig plug.
Just to be sure I wasn’t missing something when I tested it with the Digirig cable I plugged it back in and shorted it (sleeve to R2) and again nothing happened.
So, my conclusion is that the location of the ring on the coiled Digirig cable is just different enough from the contacts in the jacks on both Yaesu radios that it doesn’t work.
Finally, I connected my Frankenstein cable to the Digirig and my radio and plugged it into the computer and it worked perfectly with WSJT-X, transmitting when commanded using the TEST PTT button, the TUNE button, and when it was appropriate to transmit in FT-8 mode.
Denis, could I possibly get a replacement for the FT-65 cable directly from you or should I go back to Gigaparts?

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@K0TX - what should my next step be?

Apologies for the delay. I can replace the cable but the chances are good that the replacement will have exactly the same issue pairing with your transceiver. If you are unable to return it to GigaParts for refund, you can send it to me for store credit.

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I wondered about that. It’s odd that it works the same for both radios. I wonder if Yaesu changed their jacks at some point. I bought both radios in mid 2022. They are made in Japan.
If you switch to a two pole plug for the 2.5 mm plug I think it would work, based on my experiment.
I’m not sure that it worth the cost for shipping to return it. I’ll probably just order a cord for my FT5DR and if one of my friends buys an FT65 I’ll gift this cable to them.
Thank you for your help through this. I truly appreciate your customer support!
73 de AI7KS

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@K0TX ,
I’ve been wondering how difficult it would be to get a similar cable made except using a 2 pole plug for the 2.5 mm plug. Based on how quickly you went from discussing pin outs to stocking a new cable in this thread: Cable for Anytone AT-D578UV III Pro & Plus - #8 by K0TX
it appears to be relatively easy.

Also, I’m sorry I never thought to offer this before, would you be interested in me sending you the FT-65 cable and temporarily my FT-65 so you can see what you think?

I found below info here:

Audio IO

Motorola M1 connector

  • 3.5mm :
    • Tip = speaker- (Vcm = 2.5V)
      • Jumps to 2V when squelch is open. Audio max = 4V (with respect to GND)
    • Ring = ?
      • internal 10K PU to 3V3, unknown purpose
      • Short circuited to sleeve when using the SSM-17B Hand speaker Mic. Maybe that’s the reason why Yaesu doesn’t market the SSM-17B as an accessory to the FT-65. The SSM-512B is advised instead.
    • Sleeve = speaker+ (Vcm = 2.5V)
  • 2.5mm :
    • Tip = Connect a PTT switch in series with electret-MIC (1K8 or 2K2 internal resistance) connected to GND. Function generator outputs must be AC-coupled to this input, otherwise the PTT functionality no longer works correctly.
    • Ring = RX/TX line
      • RX/TX Short circuited to sleeve when using the SSM-17B Hand speaker Mic.
      • Use open drain TX and connect it to RX.
      • To interface to a standard UART: connect the anode of a diode to the UART-RX. Connect the cathode of that same diode to the UART-TX.
    • Sleeve = GND

This confirms that we are absolutely safe using TS (2 pin) connectors on both sides.
Now the issue you are reporting is likely to do with the mechanical fit. I did overlay of parts of the photo you shared and it confirms what you observed: that the tip part is of different length on 2.5mm side between Digirig cable and speaker/mic.

There is a good number of these cables out in the wild, but this is the first time that I remember this issue coming up. I’ll keep it in mind when reordering this model.

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Thanks! I appreciate it and I would be happy to test any revised cables.
But as far as the SSM-17B goes, that’s exactly what Yaesu lists on their accessories page for the FT65R:

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I think I found a matching connector. Will prototype with the next order and reach out for testers.


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Wonderful. Please let me know how I can help.


Hello! I am so happy to have found this thread, I had to make an account to reply right away.

I have the exact same problem with my FT-4X but kept thinking that I was doing something wrong until I was able to build a cable for my AnyTone at-778uv and confirm that it works as expected.

The cable I’m using is the coiled digirig cable that looks exactly like the one smshannon55 posted pictures of. Any chance I can get in on the replacement/testing bandwagon?


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Welcome to the forum!!

I’m sorry for your frustration, but relieved (selfishly) that I’m not the only one to have this issue. I’m not the person who can help, but I wish you well!


I’ll make an announcement in the thread when the replacement is available. Please stay tuned.


Denis got a prototype cable to me and it works.


Awesome, I’m excited to hear that it’s looking good so far.

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Hello, have there been any more updates on this?

The cable Denis sent works. I suspect that’s what he is stocking now. Maybe he simply forgot to announce it.

I have a test run of the updated cable. Please reach out to me via PM after Monday and I’ll be able to shoot a replacement.

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