SpectraLink 8440 - Chapter 6: Features that Cannot be Configured

1725-86984-000_P.docx
September 2016 59
Chapter 6: Features that Cannot be
Configured
Audio Processing Features
The Spectralink 84-Series handsets have these built-in audio processing features: automatic
gain control, background noise suppression, comfort noise fill, dynamic noise reduction, jitter
buffer and packet error concealment, and low delay audio packet transmission. These features
work automatically, without configuration changes.
Automatic Gain Control
Automatic Gain Control (AGC) is applicable to handsfree operation and is used to boost the
transmit gain of the local talker in certain circumstances. This increases the effective user-
handset radius and helps with the intelligibility of soft-talkers.
Background Noise Suppression
Background noise suppression (BNS) is designed primarily for handsfree operation and reduces
background noise to enhance communication in noisy environments.
Comfort Noise Fill
Comfort noise fill is designed to help provide a consistent noise level to the remote user of a
handsfree call. Fluctuations in perceived background noise levels are an undesirable side effect
of the non-linear component of most acoustic echo cancellation (AEC) systems. This feature
uses noise synthesis techniques to smooth out the noise level in the direction toward the remote
user, providing a more natural call experience. This feature is different from Voice Activity
Detection.
Dynamic Noise Reduction
Dynamic noise reduction (DNR) provides maximum microphone sensitivity, while automatically
reducing background noise— from fans, projectors, heating and air conditioning—for clearer
sound and more efficient conferencing.
Jitter Buffer and Packet Error Concealment
The handset employs a high-performance jitter buffer and packet error concealment system
designed to mitigate packet inter-arrival jitter and out-of-order, or lost or delayed (by the
network) packets. The jitter buffer is adaptive and configurable for different network