I want to use remote control with my 7300. This is more an experiment than an actual plan to use my 7300 from a remote location. What I am thinking is that I will use the 7300 remote control port along with a separate audio connection so I don’t have to play with virtual devices to connect the audio for digital modes. Not sure how this will work yet. It’s possible that it is not possible to do this.

This is the device I want to build. A USB to Serial adapter that connects to the remote control port of the 7300. The remote control port uses a 3.5mm audio connector with the TIP going to UART TX and RX pins and the ground connecting to the UART GND pin. The TX and RX pins are pulled high through a 10K resistor connected to 5 volts. The TIP is connected directly to the RX pin and to the TX pin via a 1n4148 diode.

The first step is to unlink the CV-I remote port from the USB data port. Second step is to build a remote control cable serial cable. I happen to have a cable with a 3.5mm stereo plug on the end that I will use for cabling. I also already have a couple of USB to UART dongles that use silicon labs chips. I will build the interface using a 6 pin DuPont header. I found this diagram on the internet from Larry WT6M that uses an FTDI chip, but it is fairly standard stuff.

Here is the DuPont header with the diode and resistor connected to the header pins. I also include the tip and gnd connections from the cable.

The ring wire (red) is left unconnected. The header attaches to the USB to UART as follows:

I tested the cable with WSJT-X installed on my mini PC (see previous blog). The dongle appears as com port COM7 and works with WSJT-X cat control. I don’t have any audio set up so I can only view the rig status and change the settings.

I already installed WFView and it appears to work with the new cable.