Icom IC-7300 USB for Radio Control + FSK Keying

There’s one thing that was annoying me about the new IC-7300, and that was that the USB connection to the computer did it all: radio control, soundcard codec, PTT/CW. That’s great, and I could run AFSK RTTY. But I really wanted to do FSK RTTY. You could do it, but you lost the radio control part of the USB cable. Many people suggested just buying yet another cable (CI-V) and tying up yet another USB port on your PC to regain radio control just to do FSK RTTY. I like a clean and efficient solution, since my push in 2017 has been to eliminate the rats nest of wiring in my station.

I did some digging in the IC-7300 forums and came across this pretty nice solution that achieves my goal of one USB connection to achieve radio control + FSK RTTY keying (along with the option of doing other digital modes using AFSK). Max, N5NHJ (I5NHJ) posted setup instructions on accomplishing this, but with one caveat: You’ll need to run VSPE to split the Com port so that multiple programs can access the same com port (Radio control + FSK).

What you’ll need:

Eterlogic VSPE (Virtual Serial Port Emulator) software. This software is free for 32bit, but the author charges $24.95 for the 64bit version. This is fine if you’re running Windows 7 32 bit, however if you’re running Windows 10, that is 64bit. You can run the software on 64bit, but each time it starts up it will prompt you to order a 64bit license. Clicking on the boxes will still let you run the program with full features, so you can pay the $25 to get rid of the two popups everytime you start up, or you can live with it.

IC-7300 Settings:

Menu > Set > Connectors

CI-V Menu

CI-V Baud Rate: 19200

CI-V Address: 94h

CI-V Transceive: Off

CI-V USB -> REMOTE Transcieve Address: 94h

CI-V USB Port: Unlink from [Remote]

CI-V USB Baud Rate: 115200   *Note, this is needed to also work with N1MM Spectrum

CI-V USB Echo Back: ON

USB Serial Function submenu: CI-V


USB Keying (CW): RTS

USB Keying (RTTY): RTS

Now that your radio is configured, make note of the Com port that was added for your radio in Windows (this is the port you use to connect for radio control). For purposes of this example, my radio’s com port is COM3. Substitute that for what your radio is using.

VSPE Setup

Start VSPE

Click on Create New Device

Select device type: Splitter, click Next

Data Source Serial Port: COM3 (or whatever the radio serial port is for your radio)

Virtual Serial Port: COM4 (or whichever you want, make sure your logging and RTTY FSK keying programs use this port).

Click settings:

Speed: 38400 (or whichever value is selected in the 7300’s CI-V USB Baud Rate)


Parity: no

Bits: 8

Stop bits: 1

Click OK

Redirect modem registers: CHECKED

Initial Modem Registers State: RTS: NOT CHECKED, DTR: NOT CHECKED

Once you’re all setup, click the Play button. VSPE should say that the initialization is OK.

You now are ready to go. To ensure that you don’t have to remember all of these settings each time you restart your computer or VSPE, save the profile to a place you can remember.

Each time you stop VSPE or restart your computer, you will have to open the saved profile. It will automatically load the settings and create your virtual com port. You can minimize this app.

For N1MM and other logging programs, I point the radio control function to COM4. I now have radio control.

FSK setup

I use MMTTY with the EXTFSK64 plugins. I won’t go into the full MMTTY setup here (as many others have covered how to use the EXTFSK stuff with MMTTY), but to get FSK keying working with our setup, choose the same virtual com port we set up earlier (in my case COM4) and check the correct boxes for FSK and PTT (FSK: RTS, PTT: DTR)

You should now have full radio control + FSK keying all from ONE USB cable to your IC-7300.

Thanks to Max, N5NHJ (I5NHJ) for the original post. I made some changes to his post based on things I used to get it to work here at my station. Max’s original post is below:

When the IC-7300 is connected to the PC it exposes 1 virtual serial port that can be configured to accept CAT commands, to send CW, to control the PTT, and to shift the frequency in FSK.

To do all this we theoretically need 4 channels:

1 channel for CAT (RX and TX signals on the com port)

1 channel for CW (DTR signal on the com port, usual choice)

1 channel for FSK (RTS signal on the com port is OK, MTTY  by default uses TX)

1 channel for PTT (hops, we run out of channels... maybe not, we can use the CAT command)

Assuming we are using more than 1 program to do all this (example is N1MM and MTTY) we need a method to simultaneously access the only available COM port from 2 different programs.

Let's start with the radio configuration. 

In the MENU/SET/CONNECTORS/CI-V configure the radio like this:

CI-V Baud Rate                Whatever you like (19200 is ok)

CI-V Addres                94h (default)

CI-V USB-REMOTE        94h (default)

CI-V USB Port                Unlink from [REMOTE]

CI-V USB Echo Back        ON

In the MENU/SET/CONNECTORS configure the radio like this:

USB SEND                DTR

USB Keying (CW)        RTS

USB Keying (RTTY)        RTS

We are done with the radio.

Let's assume the radio Com port has been configured as COM10.

So far we should be able to communicate with the radio through the CAT from any software addressing COM10.

Using N1MM and the radio break-in we should be also able to key the CW (how to configure N1MM for this is out of this scope).

Please verify if your radio follows the CAT commands now.

Now lets add more complexity, VSPE.

As said before, we want to simultaneously access the radio Com port from 2 different programs.

Run VSPE and create a splitter , the data source port will be COM10, the virtual serial port will be say, COM 20.

Verify in the VSPE device properties "redirect modem register" is CHECKED and "initial modem register state" is not set for both RTS and DTR.

Now go ack to N1MM and verify that CAT and CW are still working after changing the communication port from COM10 to COM20.

We are almost done.

Configure the RTTY software to control the FSK via the RTS signal on COM20.

To activate the PTT we just need the last trick that is to use the CAT to control the PTT. N1MM has this feature selectable, MTTY too.

We just need to activate it on N1MM because it controls the PTT.

Ad this point you have your beautifull 7300 running everything with just 1 USB connection.

Hope this helps, anyone needs more support please write off the reflector.


73 de Max, N5NHJ (I8NHJ)
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