Voip keyup *99 location

I am not looking for opinions, I am looking for technical facts. I want to add a cw character when the *99 keyup command actually is successful from a voip phone. I have *0 working just fine for unkeying, *0# is easy to send from a voip phone to unkey, and nice to know that you were successful in unkeying, now I want to know my *99 was accepted, so I am looking for the location of the cop command so I can alter it.

No can do. Not a COP command.
It’s a built-in function only when it is designated as a phone input. Unchangeable as a user setting.