Data mode communication with the FT-991

Setting up the Yaesu FT-991 and Signalink

Following on from the Yaesu FT-817 data mode set up guide, this page will take you through the steps required to set up and configure the FT-991 for data mode communication. The configuration of the FT-991 is, but there are differences which may not be evident in the manual supplied with the radio. 

Data mode communication on the FT-991
Data mode communication on the Yaesu FT-991

Hardware and software required for data mode communication

In this guide the following items are used:

  • HRD-Ham Radio Deluxe
  • Signalink USB (order with SLUSB6PM leads)
  • USB lead
  • Window PC
  • Yaesu FT-991 radio
  • HF antenna

Configure the Signalink before connecting

Before connecting up, do ensure that your Signalink is appropriately configured, this will involve taking the unit apart. It should have come with clear instructions on how to do this, alternatively go to the Tigertronics website for help.


There are four socket head screws on the front of the unit to remove, this allows you access to the configuration socket. Configuration is no problem and should not be too difficult to do. New units are supplied with precut link wires which work just fine. Alternatively, there are pre-configured adapters available which will slot right in and eliminates the need for link wires.

SignaLink configuration FT-991

Connecting up the FT-991 and Signalink

Connect your Signalink, PC and radio as follows:

  • PTT control,  received and transmitted audio is connected to the Signalink via data lead supplied with the Signalink (6 pin data socket)
  • PTT is activated by the Signalink when audio data is sent to it (like VOX).
  • Frequency control is via your normal PC control (CAT interface) lead 
Setting up the Yaesu FT-991 and Signalink for data mode communication
Yaesu FT-991 and Signalink connections for data modes

Configure your PC to work with the Signalink sound card

You'll need to install the driver and setup your Signalink sound card levels on your PC as described here: . It's fairly easy to do and should not cause any problems.

Setting up the FT-991 and the Signalink

Switch on the FT-991 and check your settings as shown below:

Menu settings:

  1. Mode set to: USB
  2. Set power to: 5 Watts (to begin with)
  3. Set meter to: 'ALC'


  1. Set all dials to 50%
  2. Switch on

Run HRD and load DM780

  1. Fire up HRD and open the DM780 module
  2. Click on 'Options', then select PTT
  3. Ensure PTT is set to 'None' - via soundcard PTT or radio VOX
  4. Then select 'SoundCard'
  5. Make sure the HRD is configured to use the SignaLink sound card (not the PC sound card):
Click to enlarge
Click to enlarge

Getting ready for a QSO

  1. Select your desired frequency to use at the bottom of the screen (40 m is a good starting point)
  2. Ensure the radio is set the USB mode
  3. Your screen should look something like this:
Setting up the Yaesu FT-991 for data mode communication
Setting up the Yaesu FT-991 for data mode communication

Trim the transmit and receive levels on the SignaLink

  1. Adjust the RX knob on the SignaLink so the waterfall displays good clear data streams. The FT-991 volume knob should have no effect.
  2. When transmitting, adjust the TX knob on the Signalink so that the ALC bar is just touching 10dB. See image on the right.
  3. That's it. You should be ready to make a CQ call.
Data mode communication on the Yaesu FT-991
Data mode communication on the Yaesu FT-991

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