Overview
This document is an attempt to explain the connections that are needed to interface a computer with the Yaesu FTDX-101D, what each of those connections does and what you need to do to get your computer talking to your rig. While it’s written for the FTDX-101D, I suspect the same information will apply to any modern Yaesu transceiver and with some minor changes could also be used to set up non-Yaesu rigs.
Connecting your computer to your transceiver allows you to do all sorts of interesting things. You can control your rig from your computer, automate the logging process, run software that allows you to communicate with others using the various digital modes and many other things.
While researching the connection process, I came across a lot of good information, some bad information and found that although many people were able to connect the two devices, a lot of them didn’t really understand what was going on when they did it. I hope to clear that up here.

There are four different connections that need to take place when you connect to your radio with each one serving a particular purpose.
The first is for CAT (Computer Aided Transceiver) control. This allows the computer to send commands to the radio and receive back responses enabling you to do things like change your rigs frequency and mode and read back parameters like SWR and power, etc.
The second connection is for keying the rig. You want your computer to be able to tell your transceiver when to transmit and when to stop transmitting so it can automatically send and receive data.
The next connection is for sending audio to your rig. This is required to modulate the carrier for digital modes or for sending prerecorded audio.
The final connection is used to receive audio from your rig. Doing this allows software on your computer to ‘listen’ to the rig, giving it the ability to do things like decode Morse code or interpret digital mode messages.
In the old days, interfacing with a radio was complex and required two different cables. CAT control took place through an RS-232 cable while RTTY/Data, audio input and output and transmitter keying were done using a special 6-pin Mini-DIN data/packet connector cable. In modern setups, both of these cables have been replaced with a single USB cable which greatly simplifies the connection process. Unfortunately, the connection process is a bit confusing because the industry has implemented the USB interface in a way that emulates the old two cable method making it more complex than it really needs to be.
On Yaesu radios, you install a set of drivers that connect to the computer hardware and present an interface through which your programs (WSJT-X, JS8Call, fldigi, Ham Radio Deluxe, etc) can talk to the radio. The driver installation creates two virtual COM ports (Enhanced COM Port, Standard COM Port) and two audio devices (Line USB Audio CODEC), (Speakers USB Audio CODEC).
Enhanced COM Port is used for CAT control. It sends commands to the rig and receives back responses allowing the computer control the radio and read the various settings and parameters. This acts as the equivalent of the RS-232 cable.
Standard COM Port is used strictly for keying the transmitter. This takes the place of the 6-pin Mini-DIN connector cable. One of the things that’s interesting with this connection is that only the DTR or RTS line is used for keying the rig, so it really doesn’t matter what setting you use for baud rate, parity, etc. (Even though it doesn’t matter, later in the procedure I use the same settings that I use for the enhanced port, just to make them consistent).
Line USB Audio CODEC sends audio information from your computer to your radio allowing it to modulate the carrier and transmit information. This connection used to be part of the 6-pin Mini-DIN connector cable.
Speakers USB Audio CODEC receives audio from your radio allowing it to decode the audio and present it as Morse code or digital mode data.
Installing and Configuring the Drivers
- Go to the Yaesu website and navigate to the FTDX101D page. Select ‘Files’ and click on the ‘FTDX101MP/D USB Driver Virtual COM Port Driver (Windows 11/10)’ link towards the bottom of the page. This should download the file ‘CP210x_Universal_Windows_Driver.zip’ to you computer.
- Right-click on the file, select ‘Extract All…’ and press the ‘Extract’ button.
- After the files have been extracted, right-click on the ‘silabser.inf’ file, select ‘Install’ and then press the ‘Open’ button and follow the prompts to install the driver.
- Open Windows Device Manager, click on ‘Ports (COM & LPT)’ and verify that you have two ‘Silicon Labs Dual CP2105 USB entries’. While doing this, take note of the COM port numbers used for each device since you will need this information later in the process. On my system ‘COM4’ was used for ‘Enhanced’ and ‘COM3’ for ‘Standard’ but your values may be different.

- Double-click on the ‘Enhanced’ port entry, navigate to ‘Port Settings’ and verify the settings are as follows, changing the values if needed. If you look around the Internet you may see many different values set for these parameters. This is because the values you use aren’t critical as long as both the radio and computer use the same values. It’s like talking to someone in French, if both of you are using speaking French, everything is fine but if one of you is speaking French while the other is speaking German, nothing good will come of it.
- ‘Bits per second:’ ‘38400’
- ‘Data bits:’ ‘8’
- ‘Parity:’ ‘None’
- ‘Stop bits:’ ‘2’
- ‘Flow control:’ ‘None’

- Double-click on the ‘Standard’ port entry, navigate to ‘Port Settings’ and enter the same values you used for the ‘Enhanced’ port.
- You can now delete the CP210x zip file and folder since they’re no longer needed.
Configuring the Yaesu FTDX-101D
- On the FTDX-101D, press the ‘FUNC’ button, then select ‘Operation Setting’>’General’.
- Set the following parameters:
- ‘CAT RATE’: ‘38400bps’
- ‘CAT TIME OUT TIMER’: ‘100msec’
- CAT RTS’: ‘OFF’

- Press the ‘BACK’ button to back out of the current screen and the select ‘CW SETTING’ > ‘MODE CW’. Find ‘PC KEYING’ and set it to ‘DTR’.

- And you’re done. These settings should allow your radio to work with any program you install as long as the program configuration matches the values you’ve used here. I’ll soon be posting setup information for other programs like WSJT-X, N1MM Logger and N3FJP Logger which will show you how it’s done.





