RS232 Digirig with Kenwood Tm-D710

Not sure what I’m doing wrong here. I have a Digirig RS232 and the Yaesu DIN cables that work with the Kenwood TM-D710… When I connect the COM cable to either the Audio or Serial output on the Digirig and connect to the device using a serial program, I get no response. I’m connecting to the back of the head unit COM port where the TNC is active and I’ve verified the COM speeds across everything. In fact I just default set them to 9600. I see no TNC responses. When I use a standard cable (RT programming cable) I’m able to connect to the TNC without issue. I’m also unable to use the cable for other data connected to the body of the radio for CHIRP access…

Has someone done this? Is this even possible?

Thanks in advance!

73 de K6EF

There may be some confusion with the terminology. Digirig is not a TNC and the serial port is used for the transceiver control (CAT) and not for the data payload.

Before we go into the CAT configuration, please connect the audio cable (MiniDin6) to the audio socket on Digirig and to your transceiver. With that you should be able to configure the software TNC such as VaraFM or SoundModem inside the shell software such as Winlink. Use PTT by RTS over Digirig’s COM port while configuring the software. Once that is all working we can turn our attention to the serial port and CAT control where available.

Hi Denis,

Thanks for getting back to me. I’m able to use the TM-D710 to send via RTS it PTTs just fine with software like Winlink. What I’d hoped to do was either use the serial connection from the digirig to CAT control the radio OR use the serial connection to connect to the radio’s TNC and run commands to connect to packet nodes. The basic connection using the “audio” side of digirig works as expected. So I’m wondering about the “serial” side.


Looks like TM-D710 is using different MiniDin8 pinout for serial port from that in Yaesu:

Here’s Yaesu FT-8xx:


Here’s Kenwood TM-D710:


Note TXD and RXD swapped around and also CTS and RTS now available. I’m going to prototype a cable. I have mailed you a prototype cable with the updated pinout. Please let me know if that addresses the issue.

Wonderful! Thank you so much! I’ll let you know as soon as I get it. On the upside, I’m about to order a Yaesu HF rig soon, so these yaesu cables will get lots of use too.

1 Like

Sounds like a plan. Depending on the model, for your Yaesu you’ll likely need Digirig configured for logic levels (default).

Hi Denis, I got the new cables today (FAST!) and was able to use the Kenwood cable to successfully connect to the COM port on the back of the TM-D710 head and interact with the TNC. Note, even though the COM port goes up to 57600, I was not able to get a working connection until I backed down to 9600. Not really an issue, just something I noticed. Thanks again!

Thanks for the confirmation. I’ll get a batch of these cables ordered. The TM-D710 kit should be available in store a few months.

1 Like

This cable kit is now available in store:

1 Like

Hi - Just received my Digirig and cables today and need some help from those of you that have used it with the D710. I plugged both the PC and data cable into the back of the radio, and have my data speeds set to 9600 baud. What settings in VARA FM do I select for PTT? When I select CAT, there is no Kenwood TM-D710 listed to select from. I tried just selecting one of the radios and clicking RTS but it triggers PTT immediately without any interaction. So - any help you can provide would be great!

Even if CAT is available I would recommend to first configure and test the setup without it. Select “none” from the rid dropdown and in PTT configuration. For basic setup info with VaraFM, please see this video:

So the good news is that I got it to work with winlink / vara - but have not been successful at using this for FLDIGI - I can’t get the PTT to function there. I didn’t have much time to play around with it today yet.

1 Like

Sounds good. When you have a moment, please post your FlDigi configuration screens pertaining to CAT and PTT and we’ll go over them.