This read-write value sets the echo cancellation delay, in milliseconds from 0 to 64, and only applies while hwVoIfConfigEchoCancellationSwitch is enabled. It should be tuned to match the round-trip echo delay of the connected line or trunk, since too short a delay setting leaves longer echoes uncancelled. For example, an admin serving a voice port over a long analog local loop might raise hwVoIfConfigEchoCancellationDelay above the default 32 ms to cover a longer echo path.