Is the rig going to transmit? Does the TX/RX button on the rig turn red?
If so, have you set the audio path correctly? When you connected the IC-7300, it should have created two audio ports as well as the COM4 port. You need to connect the audio ports ¨C indicated as USB Audio Codec or similar.
It helps to rename these codec ports as IC-7300 TX and IC-7300 RX or similar so that you know what they are.
I am trying to setup FLDIGI with the 7300 Icom. I have the rig control in FLRIG set correctly . The program is reading the freq with no problem. I have my radio set at com4. But I am not getting any power out put. I have the 7300 set at com4 19200 Radio USB Data-1. Any help would be appreciated