(Page 10 of 18 in this chapter)

2.9 Echo Cancellation

Echo cancellation improves the ability of the DTMF detector to recognize digits during playing, a capability referred to as DTMF cut-through performance.
Echoes are usually generated by poor impedance mismatch between hybrids and physical telephone lines. Echo cancellation improves cut-through performance by removing near-end echoes from the input port stream.
The echo canceller also improves cleardown detection during a play operation.
Echo cancellation is not enabled or disabled with a function call. It is configured as part of starting a protocol. When the protocol for which it is configured is started, the echo canceller is started automatically when a call enters the conversation state. Refer to the AG Access Developer's Manual for further details.

(Page 10 of 18 in this chapter)