Digium, Inc.
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Chapter 1: Overview
Echo-Cancellation
Administrators connecting their Gateway Series appliances to the PSTN
or other devices are likely to be placing calls that will result, at some
point, in an unbalanced 4-wire/2-wire hybrid. The result of this hybrid is
the reflection of a near-end echo to the calling party. Elimination of this
echo is the responsibility of echo cancellation.
The Gateway Series appliance utilizes hardware-based voice processors
for echo cancellation and codec transcoding. Its hardware echo canceller
is designed to handle up to 128ms of echo cancellation across all channels
and provides a G.168 compliant echo cancellation solution.
If not explicitly disabled in the Gateway Series web GUI, the hardware-
based echo canceller will automatically operate and cancel all network
echo within its tail range (1024 taps).
