Be careful not to touch any controls on the front of the radio, this will cause HRD to stop control, if DM-780 is running at the time, it will lose control of PTT, and you will need to reset it by operating the HRD control interface, a quick touch of the button will reset and cause the radio to go into TX mode, touch the button again and the system will return to RX mode and HRD will work properly again, DM-780 will function properly again.

Start up HRD, and set the Radio emulation for, baud rate, radio address, (These are the radio default settings, be sure the radio is set to these, they can be found in the menu.) When you have done this, you can connect to the radio with HRD, it should come up in a few seconds on the screen, test all functions. This would allow the use of other software control programs that are not USB compatible. You can use D1 for USB control, D2 for mic/acc control (with an external PC interface like Rigblaster, Signallink etc.), and D3 can be yet another configuration if the user desires it. You have three 'Data' modes which can have different settings within the radio.

See the manual for how to get to these setting. Set the radio to LSB D1 mode, in VFO mode (not memory mode). (do not change settings that are not mentioned here.) Set up the 7600 by entering the menu and setting the following settings: USB audio SQL, USB mod level, Data 1 mod. Download and install the ICOM USB driver, from the web site, following the installation guide. 'Using the IC-7600 with Ham Radio Deluxe (v4&5) with full USB control. His website is down now but I kept the text and am reposting here for safe keeping and to help fellow amateurs get this working. KK5DR wrote this great article on how to connect the IC7600 to Ham Radio Deluxe.

Ham radio deluxe setup