Audio In/Out

You also need an audio interface to send and receive the data (Audio tones) to and from your rig and this is done by connecting your rigs audio output and input to your computers sound card.

DM-780 requires the use of a sound card and some type of interface to connect the sound card to the radio. Although the computers built-in sound card can be used, it is recommended that you either use a soundcard built into your radio (preferred, where applicable) or connect a second sound card to your PC. The second sound card can be either internal or external. The advantage of having the second sound card is that it can be used for your digital communications while eliminating the possibility of transmitting unwanted computer sounds. You would also be able to listen to music on your computer while still operating in the digital modes.
Next we need to interface the sound card to the radio. Interfacing can be done in so many ways that it would take days to plow through all the available information. You can do a Google search and find hundreds of articles on the subject. It is possible to connect your radio directly to your sound card without any form of isolation but it is not recommended. We’ll assume that you want to do things properly, so here is a home brew circuit that has proved its worth many times.
This solution will work with any Icom or Yaesu rig that has a 6-pin mini-DIN connector for external audio. It will work on just about any other rig but you will have to modify the connections to your radio. If you plan to use the circuit below, please check the actual connections to the mini-DIN connection of your rig.
Note: HRD Software LLC does not accept responsibility for damage to your rig should things go wrong.

Page-177-Image-343.png A proven audio interface: Cheap and easy to build

You should always use the rig’s high-impedance audio output if there is one available. This supplies a constant signal level to the sound card. Most rigs also have a TX audio connector independent to the microphone input: you are advised to use this input. Some commercial interfaces don’t allow this: It is recommended that you avoid any interface requiring use of the microphone connector and speaker output of your radio unless there is no other option for getting the audio signals to and from the radio.

Commercial Interface Solutions

There are also some very nice commercial solutions available for interfacing the radio’s audio to the computer.
Timewave Technology has a very good reasonably priced CAT rig control product called the HamLink USB which allows rig control. As with all CAT rig control interfaces, the level of rig control is controlled by the capabilities of the rig.
Timewave also offers the PK232SC - which has a built in sound card and CAT rig control. This unit has many other useful features such as Digital Signal Processing which helps clean up the audio signal. More information can be found at their website: 
Tigertronics provides two different interfaces. One has a built-in sound card and one does not. The advantage of having an interface with a built-in sound card is it frees up the computer’s internal sound card for computer audio, such as listening to CDs, while using the external sound card for the digital modes.

Page-177-Image-344.png SignaLink Model SL-1+

The SL-1+ connects to your computer's sound card and to your radio's Mic, Data or Accessory Port. It is designed to work with ALL computer sound cards, and with ALL radios. The SignaLink SL-1+ is compact, low powered and fully isolated for optimum performance. It supports ALL sound card Digital and Voice modes, and does NOT use a serial or USB port!

Page-178-Image-345.png SignaLink USB

Note: Neither SignalLink product interfaces with the radio for CAT control. These are soundcard only interfaces.
The SignaLink™ USB combines the legendary performance of their SignaLink SL-1+ with a state of the art “built-in” low-noise sound card. The SignaLink USB has only one USB connection to the computer, and in most cases, only one connection to the radio. Convenient front panel controls make setup and operation very easy. The SignaLink USB is fully isolated and is compatible with ALL radio Mic, Data, and Accessory Ports, and supports virtually ALL sound card Digital and Voice modes. Both of the above interfaces are available on the Tigertronics website at
Another commercial solution to interfacing the radio’s audio to the computer is the Navigator.

Page-178-Image-346.png Timewave Navigator

The Timewave Navigator interface is available on the web from Timewave. The website is at The Timewave Navigator is a high quality interface between the rig and the computer, for use in running the digital modes such as PSK31, Olivia, MFSK, Hellschreiber, MT-63, etc. It also works fine for SSTV.
The Navigator interfaces to the rig using a USB port, thus it does not require a serial port on the computer. The Navigator has a built-in sound card for audio from the radio to the computer. It also provides CAT control to the rig via a serial connection from the Navigator to the rig. The Navigator is completely configured and defined in software, and future updates are expected to be flash-ROM updates that can be installed by the user.
The Navigator is also directly supported by DM-780 by clicking on Program Options and then selecting Navigator from the list of options on the left side of the window.

Page-179-Image-347.png microKEYER II

The microKEYER II™ is the most powerful single radio All-In-One USB interface and the only USB interface to fully support voice operation including microphone switching. With an single USB port, micro KEYER II™ works with any Windows based logging or control program for CW, voice, FSK and digital (RTTY, PSK31, SSTV, OLIVIA, MFSK, WSJT, etc.) operation. micro KEYER II™ includes a radio control interface that supports all standards (RS-232, CI-V, Kenwood and Yaesu TTL), a powerful CW memory keyer using K1EL's WinKey, a Digital Voice Keyer, two channel audio for transceivers with dual receivers, automatic microphone selection, and a buffer/sequencer for amplifier or LNA control. microKeyer II is available from the MicroHam website at
West Mountain Radio offers several RIGblaster products with various features. Visit their website at for more information.
Note: Because West Mountain Radio control the radio in a slightly different manner we had to add special support for these interfaces. Please visit the Options in Ham Radio Deluxe and select the COM Port TX tab then click the West Mountain - RIGblaster support box (See image below)


Other companies who provide audio interfacing solutions that work well are:
If you choose to use one of the commercial audio interfaces, make certain you follow the manufacturer’s instructions carefully for installation and set up.

Program options overview