Authorized Self-Study Guide Cisco Voice over IP (CVoice)

Configuring Echo Cancellation

Echo cancellation is configured at the voice port level. It is enabled by default, and its characteristics are configurable. Echo cancellation commands are as follows:

• echo-cancel enable— Enables cancellation of voice that is sent out through the interface and received back on the same interface. Sound that is received back in this manner is perceived by the listener as echo. Echo cancellation keeps a certain-sized sample of the outbound voice and calculates what that same signal looks like when it returns as an echo. Echo cancellation then attenuates the inbound signal by that amount to cancel the echo signal. If you disable echo cancellation, it will cause the remote side of a connection to hear echo. Because echo ...