CAT Protocol Converter

A Java multiplatform application used to convert CAT commands between a transceiver and a CAT application

Version 0.2

Included configuration is used to control Yaesu FT-991 transceiver using the latest free version of HamRadio Deluxe (v5.x), with some limitations.

Dan Toma - YO3GGX -


This is a very simple to use multi-platform Java application which can be used to convert CAT commands. It can be used to allow controlling newer transceivers using old application (no more updated). The application is user configurable for different transceivers, no matter the CAT protocol used.

As an example you can work in DigiModes using the latest free version of HamRadio Deluxe Suite ( with the new Yaesu FT-991 (which is not supported in that version of the application) using the Yaesu FT-950 model in HRD. Without this application, you will not be able to set or read the frequency from the radio as the number of digits used to represent the frequency is higher for FT-991 (as it covers VHF and UHF bands too) making this application almost useless for the new transceiver.

NOTE: As an alternative, you can buy the latest HRD version which includes 1 year of support from:

which natively supports the Yaesu FT-991 transceiver. If you are like me and you like the old free version, then go further with the reading.


Current version of the application has the following features:


Current version of the application has the following limitations:


Use this application on your own risk. If you write wrong conversion rules in the configuration file, you can send commands that can brick some transceivers.

Preparing the system

In order to use the application, you need two virtual COM ports. For this purpose, I recommend you to use the well-known open source solution named com0com.

To be able to install com0com on Windows 7 or higher, use the latest available version of the signed package available here:

or this direct link:

This is a package available only without GUI, so to install it do the following (as described in the article from the link above):


install - -

Once the driver is installed, two connected COM ports will be created: CNCA0 and CNCB0. As HamRadio Deluxe (for example) does not support such names for COM ports, rename CNCA0 to COM22 (or any other not used COM port in your system). For this, do the following:


change CNCA0 PortName=COM22

You have now two new COM ports (COM22 and CNCB0) virtually connected. You can see the two devices in the Device Manager under “com0com – serial port emulators” as in the picture below.

Download the application

You can always download the latest version of the application from the link available on my web page:

The package is a zip archive containing two files: catconv.jar and catconv.cfg.

Unzip the two file in a new folder of your choice.

Starting the application

To start the application in Windows, if you have previously installed Java Runtime (from Oracle), just click on the file (catconv.jar). You will get the following window:

Note: This application was tested with Java SE Runtime Environment 8u92 downloaded from here:

Configuring converter parameters from the GUI

Select the virtual COM port previously created (named CNCB0) as the “Bridge COM Port”. This will be used to connect to HamRadio Deluxe.

Select the COM port used by your transceiver CAT interface as the “Radio CAT Port”. This will be used for the communication with the radio.

In my case this is COM10. In fact is the port named “Silicon Labs Dual CP210x USB to UART Bridge: Enhanced COM Port (COM10)” in Device Manager.

Select the Baudrate. Use the value configured in the radio CAT setup menu. I recommend you to use the higher available speed.

Yaesu FT-991 require to set RTS in order to control it over CAT using the USB connection. For this purpose, in the File menu verify that “RTS Power” to be checked.

All settings are saved in the configuration file and automatically used at next application start.

You are now ready to use it. Do not check “Autostart” before you are sure that everything work as expected. Click on “START” button. The window background will go green and the converter will become active.

Configuring Yaesu FT-991

Use the following document to configure the settings in FT-991.

Discard the section related to the HRD version 6 configuration.

Configuring HamRadio Deluxe free version (5.28)

You can download the latest free version of HamRadio Deluxe ( from this web page:

or if the page is not available using this direct link:

Start HamRadio Deluxe. You will be prompted to define a new transceiver connection. Define the preset as in the following picture. Use the virtual COM port defined previously and FT-950 as the radio model. You don’t need to check “RTS” as this line will be controlled by the java application.

Click on “Connect” button to connect to the radio through the CATconv application.

You will be able to use most of the functions in HRD 5.x with your new transceiver.

The configuration file

When you download the application from my web site a special configuration file is included (catconv.cfg).

This contains all the settings required for the FT-991 to FT-950 conversion and looks like the following:

#Wed Jun 29 16:18:04 EEST 2016







sRadio1=Yaesu FT-991

sRadio2=Yaesu FT-950








Some of the parameters are self-explanatory, corresponding with the ones from the GUI.

I will describe here only the ones related to the conversion rules:

‘sRadio1’ – The friendly name of the transceiver to be controlled through the converter

‘sRadio2’ – The friendly name of the transceiver mode used in HRD

‘n12’ – number of conversion rules for the data passing from Radio1 to Radio2

‘n21’ – number of conversion rules for the data passing from Radio2 to Radio1

‘1xx’ – conversion rule for the data passing from Radio1 to Radio2. You can have up to 99 rules.

‘2xx’ – conversion rule for the data passing from Radio2 to Radio1. You can have up to 99 rules.

Rules syntax is based on specific tags and has the following format:

More tags will be added in the future if this will help extend the support for other transceivers, based on users feedback.

Application history

Version 0.1 (Jun 29,, 2016).

Version 0.2 (Jul 1, 2016).

What’s new/changed from 0.1:

Solved bugs:

catconv_v0.2.pdf Bucharest, Jul 1, 2016 – © Dan Toma – YO3GGX –