My radio club, SFARC, has helped me get into an HF rig, namely the Kenwood TS-440S. This radio is a bit old (1986ish) but, IMHO, this thing is awesome. It has a fairly compact form factor, runs of my 12V off grid power without issue, and with the following upgrades will talk to my computer.
I first purchased a digimode cable that has opto-isolated audio input/output as well as a USB PTT coupler which is allowing me to experiment with digital modes on this transceiver. While this is great, I would like to be able to view and control the frequency of my radio from FLDIGI via HamCAT or hamlib. Turns out this will require a little bit of hacking (awesome!) to get it working.
Issue #1: The 13 pin DIN, ACC 2, only provides audio and PTT functions. If I want to provide a serial interface I need to use the 6pin DIN, ACC 1, interface. I need to build an interface cable.
Issue #2: This interface is a serial connection using TTL voltage (5.5v) but with the same logic as a standard serial port. I need an FTDI breakout board with inverted logic.
Issue #3: The 440 requires an upgrade kit (IC-10) to provide serial communication capabilities. This kit is semi-rare and costs about 50 bucks.
In this article issue #1 will be addressed with a six pin din plug ordered from amazon.
Issue #2 will be handled by an FTDI USB board I already have on hand and an XP virtual machine running FD_PROG to invert the logic. Unfortunately this makes this solution NOT 100% Linux. To resolve this I will use the command line Linux program
ftdi_eeprom to clone my firmware and post it here so Linux only users can use
flashrom to program their FTDI boards with ease.
Issue #3 is easily resolved by ordering the chips individually or by purchasing one of my $15 IC-10 kits from eBay.
#1: Build the plug.
After receiving the plug from Amazon, I repurposed a shielded USB cable to build the plug. I hooked up all the wires even though CTS/RTS were not required. RFU style as it were. Perhaps adding flow control in the future would speed things up. I don’t know I haven’t tried. Anyway….
These are the pin numbers as viewed from the solder side:
Here is how I hooked up the 5 wire USB cable:
- GND -> Cable shield
- TXD -> Green
- RXD -> White
- CTS -> Black
- RTS -> Red
#2: Install the chips.
After I received my chips, I installed them following this guide. To sum up, remove the top and bottom cover from the radio. Then remove the face-plate screws and then loosen the 5 small screws for the metal grounding plate so it may be removed. Once this is done the chip slots will be exposed ( they are the only two empty slots on the back of the face-plate ). You will need to use a flat surface to bend the pins slightly inwards so that they will line up with the sockets when you insert them. Pay close attention and make sure the chips are fully seated properly into the sockets.
Once this is done reassemble the radio and ensure that it is working properly. Now the ACC 1 port has serial com capabilities.NICE!
#3: Hook Up the FTDI Breakout Board
The only pins required for communication are GND, TRX, and RTX. You supposedly can use a 5 wire connection using CTS/RTS flow control but it is not necessary. The FTDI breakout I used for this project only made CTS and DTS readily available so I went with the three wire setup. There may be advantages to having flow control and I would be interested to hear input on this in the comments.
Attach the TX from your rig to the RX on the FTDI and the RX from the rig to the TX on the FTDI. GND goes to GND.
#4: Program the FTDI Board
Although the wiring is done, we still need to invert the logic on the FTDI board. There is no linux app to easily do this so I ran the FD_PROG utility using an XP virtualbox install to run this program. There are multiple drivers available from FTDIChip, make sure you use the correct driver for your system.
If you don’t have a windows install to program your FTDI chip, you can flash the following firmware to your FTDI chip using
ftdi_eeprom. This firmware has the inverted logic necessary to communicate with your rig.
Download both files to the same location, plug in the FTDI and program it. Something like this:
ftdi_eeprom --flash-eeprom ftdi.config
#5: Time to play radio!
You can now use FLDIGI or similar to read/send the frequency and PTT key your radio. Software config is beyond the scope of this article, but this is what it looks like:
If you enjoyed this article you can support me by subscribing to my YouTube channel and/or visiting some links from my sponsors. Thanks!
- FTDI Chip Utilities
- FTDI Chip Drivers
- Installing an IC-10 kit into a Kenwood TS-440S/AT HF Radio
- TS 440 Serial Communications Interface
- TS-440 SAT Modifications
- Kenwood TS-440 mods reviews software and diagrams
- Build an Easy USB Computer Interface for Your Old Kenwood Rig