The IC-9100 that I have has a USB port on the back that allows audio and cat control directly from the radio. It works as advertised, and works generally well.. BUT.. a number of the software programs I like to use (WSPR) don’t have CAT radio TX control, they use the RTS method. I had given up on the radio usb method and purchased a SignaLink which did the job.
Recently I stumbled upon this website from Barry K7BWH that pointed to a bit of software from a UK Ham John, G8BPQ that creates a virtual com port and converts the RTS method to C-IV Cat Commands and makes the radio TX! The software is called CAT7200, and was initially designed for the IC7200 radio, it works on any of the recent Icoms with built in USB port, the IC9100, IC7410, IC7200, 7600 and IC7100 etc.
John’s website says
CAT7200 converts changes in the RTS signal on a Virtual COM Port to ICOM CI-V PTT commands. It allows sound card based digital modem programs, such as the UZ7HO soundmodem, which do not support PTT via CAT commands to be used with ICOM radios with built in sound cards. It was originally written for the ICOM 7200, but has also been tested with an ICOM 7100/7410/9100. The Program works in conjunction with the "User Mode Virtual Serial Port Driver" from the BPQ32 Node package.
Follow the instructions on both Barry and John’s website’s and install the virtual serial Port. Some have reported issues with unsigned drivers and windows 8, the websites have tips on how to solve those, i didnt have any issues on my setup, the below is my apple mac using a virtual machine inside parallels and windows 7 pro 32bit. the websites show how to set up the radio also, with menu settings etc, make sure its using the [D] Digital mode.
Then in your software, select the RTS method for PTT and the application (virtual) com port you have created (com9 for me).
And run your software and it will work, This demo is my own WSPR-X setup for windows. when the software transmits, the control program takes over and it all works!
Thanks to both John and Barry for the software and the original guide.! Enjoy.