Correct me if I’m wrong but companding is nothing more than compressing and/or inversion, companding is not cypher. In fact when any of those radios are in companding mode you can still make it out if your hearing is good something mine isn’t most audio signals are garbled to me lol
For a guy who likes to correct me for specifics you’re conflating companding as CT
I don't like to correct you. I don't even
know you. I do know that people will find this thread researching those toys, read what you said because you said it like you knew it to be correct, and then later on I'll hear it again in other forums and places and eventually it will become 'fact'.
I'm just rebutting you coming in here with very little actual knowledge of these things.
Companding was pretty cool back in the day. You may have heard of 'Dolby', that's the most famous use of it. It only works when both sides have the capability, and have it activated. You are correct when you state companding is not 'cypher'. You can still understand a companded audio output, it will just sound very flat and narrow. (I think I have some dbx rack gear in storage)
The scramble mode of these radios is a simple circuit that inverts audio around a certain frequency. The radio on the other side does the same thing to recover the audio. Better versions use a shifting inversion point. There is no compression involved. There is no companding mode. I own several of these devices. Some of the best were made by a company called Midian.
Depending on where the fold point is, you can sort of even understand the inverted audio, especially using larger speakers.
comsec nerds like to argue whether or not inversion is 'encryption' or merely voice protection. That's probably a great topic to spin off in another thread, though.