Digirig + Kenwood TS-570D

Digirig’s Kenwood cable works fine for audio and PTT with this transceiver so it is possible to enjoy the digital modes in the minimal configuration. Unfortunately TS-570D’s serial COM port doesn’t work with Digirig using the popular digital modes software options.

This gets somewhat technical for those interested. It took a lot of coffee and a logic analyzer to figure it out.

Background:

  • The radio uses DB9 serial port with RS-232 level signals. The baud rate is configured in menu #35 and ranges from 1200 to 57600, most with 8N1 configuration.
  • For simplicity Digirig only uses two serial port data lines (TxD and RxD) and none of the legacy hardware flow control lines for their intended purpose (CTS, RTS). This works for pretty much every(*) CAT enabled transceiver under the sun because they handle the commands as they come in real time.

The issue:

  • TS-570D is veeeery slow in handling commands over serial CAT port.
  • Digirig supports no connections for hardware flow control lines so when transceiver signals that it is busy (Clear To Send is inactive), the traffic doesn’t stop.
  • If new command comes in while previous command is being processed the transceiver becomes unresponsive and doesn’t recover until rebooted (bad implementation).
  • There is not enough adjustment range in popular software to space out command to the point that TS-570D can reliably handle them as they come. I tried WSJT-X, Omnirig and Flrig (most flexible timing adjustments and lasts the longest before chocking, but still no Champaign).

See how the transceiver is being bombarded by the commands (yellow) and keeps up for some time with responses (blue) in the beginning, but then stumbles and becomes unresponsive:

If optional serial CAT control is desired, you’ll need a separate USB/RS-232 DB9 dongle with the hardware flow control lines supported.

Other Kenwood TS-570D’s menu settings of interest for setting up Digital modes:

  • #33 - AF input level
  • #34 - AF output level
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@K0TX Thanks so much for this info. Stumbling across this saved me a lot of time doing similar diagnosis. Would it be possible to update the product description for these cables to clarify digirig’s level of compatibility the TS-570D?

I don’t own this rig, but thanks for the great demonstration of troubleshooting. Thanks for going the distance to use a logic analyzer to diagnose this subtle issue.

73 Constrainted

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I’m not experienced with CAT control.

Is the problem you have uncovered here really a poor implementation of CAT command processing, or that CAT command processing is poorly specified? Is there a reference? A reference implementation? The truSDX seems to take the Kenwood TS480 CAT command set as a sufficient set to emulate.

This troubleshooting comment really shows that I have a lot to learn about CAT control.

73 Constrainted

The command set is ok. The issue is with the underlying serial communication and radio’s handling of errors.

  1. Radio’s handling of the CAT is way too slow (or receive buffer too short) so that it needs to rely on the hardware flow control to pause sender when it needs more time (busy/full).
  2. Digirig doesn’t offer connections for hardware flow control (CTS/RTS). Those are legacy signals and none of other radios require them.
  3. Radio doesn’t recover gracefully from communication errors and requires reboot after overflow.
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K0TX, interesting!
I am trying to use the digirig with my TS-2000. Similar cat set up. I can get the combo to do either rig control OR PTT but not both at the same time. I am using Windows 7 Home Premium. The way I have to use to it is with a separate RS-232 port for rig control and only use the digirig for sound and PTT. Is there any hope for just using the digirig for both?

I saw a schematic for the digirig on the site that seems to show the possibility of using the RTS to trigger the PTT output of the digirig other wise it seems to be triggered my something else.

Any thoughts or help?
Dave K3GAU

David,
What happens when you configure Digirig for both CAT control and PTT?

GE Denis,

I have just today got it to work with everything going through the Digirig.
Let me give you a bit of an explanation. I have been running the TS-2000 using various digital modes for 16 years or longer. I first started using a home brew interface and then for most of those years using a SLUSB interface. One thing you learn early on is that you CAN NOT use a PTT going through the RS-232 connector on the back of the rig. To do digital modes with the audio going in the ACC plug (13 pin), the PTT MUST go in on pin 9 of the ACC plug! If you send a PTT command through the serial port it mutes the audio going in the ACC plug.

With that in mind, I tried using the same port for both rig control and PTT without sending a command via the rig control program. It didn’t work. I could get either rig control or PTT but not both at the same time. Finally today, after reading the info on your site and looking at the basic schematic for the umteenth time, it dawned on me that the digirig would not pass the RTS signal to the rig and I could use it for PTT. So when I set the rig control and PTT of the digital mode programs as shown in the attached picture everything worked as it should.

It sure have been nice to have that stated somewhere on the site implicitly rather than having to piece it together from various comments.

Dave K3GAU

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Thanks for reporting the details of your working configuration with Digirig.

73 Constrainted

Folks,

I’m currently running a TS-750D on a Digirig mobile v1.9.
CAT-control is not my problem, but I’m not getting the full audio bandwidth delivered through the ACC jack. Menu #32 (Digi filter) is OFF.
Does anyone have any ideas about this - what am I missing?

73, Stefan | DK5SM.

uuh, shame on me - had the IF shift turned somewhere. Everything is fine now. :wink:

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I’ve been reading/researching/troubleshooting my Digirig/TS-570D interface while using JS8Call. I understand that the TS-570D really needs to use the legacy RTS/CTS handshaking signals for proper communication. As mentioned in other comments, Digirig does not provide those legacy control lines in the DB-9 cable interface. I tried various slower baud rates (9600/4800/2400/1200), handshaking configurations, etc. The rig control would work for a while, but after 30 min to 120 mins (randomly), I would receive the infamous “Rig Control Error” and the TS-570D would become unresponsive. A TS-570D power recycle would alleviate the problem for a while, then it would happen again. Thinking it is a bus timing problem, I decided to increase the Baud Rate to 57600 on the computer port and on the TS-570D to match. It worked and I have NOT received a “Rig Control Error” since. I have no way to verify what the bus timing looks like as I do not have a logic analyzer. I’ve let JS8Call (40M) run continuously for several days, and I no longer receive any “Rig Control Error” messages. The CTRL (computer control) indicator on the TS-570D front panel stays on continuously now, as before it would disappear when the TS-570D became unresponsive. So, I am successfully using the Digirig interface for both CAT control and audio with no hardware flow control lines.

Maybe K0TX (Denis) can test this set up with his logic analyzer with a TS-570 like he did previously and see what is really happening to the bus timing at 57600?

My current TS-570D JS8CALL (also WSJT-X and Fldigi) set up is:
CAT Control: 57600-8-1, Handshake - None, Force Control Lines: blank.
PTT Method: RTS checked, Mode - USB, Split Operation - None.

I certainly hope this information helps.
I know that I am having fun with these digital modes and using older radios for this makes it a challenge.
The Digirig interface makes it easy to get control of your rig.

Good luck and 73.
Dano - KF0YV

Dano,
Thank you for your report. Another common reason for “Rig Control Error” is RFI disruption serial communication. Just switching to a different band can cause issue to go away in some cases. If you only received the message while transmitting, but never before first transmit attempt then it’s a strong indication that you may be dealing with RFI.

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