The codecs sound great, but Im told I need a mix-minus to get rid of echoes at the remote site. What is that?

The concept is simple. Don't send the audio from the remote back to the remote. Give them everything else they need to hear but not their own audio.

This means that the "cure" is at the studio end, not at the remote. See Tech Tip 220 for more information.

I cant really gove you an answer,but what I can give you is a way to a solution, that is you have to find the anglde that you relate to or peaks your interest. A good paper is one that people get drawn into because it reaches them ln some way.As for me WW11 to me, I think of the holocaust and the effect it had on the survivors, their families and those who stood by and did nothing until it was too late.