C Packet Control Features
Jitter Buffer
When voice signals are packetized and transmitted, individual packets can take different paths through the
network and arrive at the destination at varied timings. This is referred to as "jitter", and it can cause degradation
in speech quality. To compensate for jitter problems, the "jitter buffer" accumulates the packets temporarily for
processing.
To set the size of the jitter buffer, refer to "3.4 [1-1] Slot—Card Property - IPCMPR/IPCEMPR—VoIP-DSP
Option" in the PC Programming Manual or the On-line Help for your PBX.
Voice Activity Detection (VAD)
The VAD conserves bandwidth by detecting silent periods during a call and suppressing the packets of silence
from being sent to the network. This feature can be enabled or disabled for codec G.711.
To configure the VAD feature, refer to "3.21 [1-1] Slot—Port Property - Virtual IPCS—Voice Activity Detection
for G.711" in the PC Programming Manual or the On-line Help for your PBX.
Note
To use the VAD feature for a certain codec, be sure to enable it for that codec on both the local and remote
gateway devices.
Document Version 2009-12
Quick Installation Guide
79
C Packet Control Features