Manufacturers have had built-in Voice Keyers for some time now, Icom have had it in various radio models with varying functionality. Voice Keyers are useful for many types of operating, contesting being the main one.
As mentioned, Icom, have implemented the functionality of their Voice Keyers in various ways, but in all radios a specific Voice Keyer memory can be triggered when a specific resistor value was connected between the microphone pin 3 and ground.
However, radios like the IC-756Pro3 did not have any auto repeat function in its Voice Keyer, for radios similar to this, the Voice Memory would only send once, this means you need to press a button each time you wanted to send a voice memory. To automate this on my Icom IC-756Pro3, I designed, built and published a auto voice keyer box; http://geekhouse.weebly.com/pic-project—icom-auto-voice-keyer.html
I also own an Icom IC-7300, and this model has an auto repeat function with a setting to change the gap between each memory keyer. If the memory button (on the radio or via the remote) is pressed for < 1 second then the radio only send the voice keyer memory once. If pressed for > 1 second then the voice keyer memory is sent and repeated until a button is pressed to cancel it. For this I made a simpler Icom voice keyer project; http://www.geekshed.co.uk/icom-external-keypad/
There has never been a documented command to send the voice keyer memory until the release of the Icom IC-7610. In the “IC-7610 CI-V Reference Guide“, there is a CI-V command called “Voice TX Memory” which can send any of the Voice Keyer Memories numbered 01 – 08, sending 00 cancels the current memory playback..
Our [homebrew] Camb-Hams logging software, CamLog, has the feature for when used with an Elecraft K3 that pressing the F1-F4 keyboard keys on the keyboard will tell the radio ,via CI-V, to send the voice memory 01-04. While on the Camb-Hams 2018 DX’Pedition, the logging software was updated to add the same functionality for the Icom IC-7610 we had, which worked. Being curious, I the tested this functionality with my Icom IC-7300 and it works! To be clear, the CI-V command for sending a voice keyer memory on an Icom IC-7610 works on the Icom IC-7300
Taking the Icom IC-7610 CI-V command for the Voice Keyer, and changing the values etc for the Icom IC-7300, the CI-V command to send the message in Voice Keyer memory 1 is;
For memory 2 it is;
And to cancel a memory during playback, then use this CI-V command;
Thanks to George M1GEO for pointing out this CI-V command on the IC-7610, and to Rob M0VFC for implementing this CI-V command into CamLog.
I hope this helps someone.