WebRTC technology enables transmission of full duplex audio over the internet - just using your browser - in this case we are going to use MORSE CODE AUDIO TONES instead of voice -
Here is a free WebRTC website that you can test, invite a friend(s) to join you here and try it out.
To send a sidetone instead of your voice, all you have to do is run an audio cable from your sidetone generator to the MIC INPUT or LINE INPUT of your sound card. Adjust the volume accordingly so that you don't overdrive and distort the transmitted audio.
When you click on the link, it will ask your permission to use your MIC, click YES. (Video is optional, you don't have to use your camera, it gives you an option to turn your camera off.)
To change the MIC input soundcard device, click on the CAMERA ICON (rt side of the address bar ) and then reload the browser.