How does the remote terminal clear the echoes of the audio signal?

There are echoes when the signal is sent to the remote terminal through the AUX of the Mixing Console. To clear the echoes, you could follow the solutions below:

1: Confirm the input interfaces of the Mixing Console for remote terminals.

2: Turn on the AUX channels of the input interfaces confirmed right now.

3: Flip on the main AUX control switch of the Mixing Console.

4: Turn off the AUX channel for the remote terminal to the Mixing Console input interfaces

5: To check whether the remote terminal unit turns on the echo cancellation or not.