Silence Suppression And Comfort Noise Generation; Configure Dial Plans - Cisco WRP500 Administration Manual

Silence Suppression and Comfort Noise Generation

R E V I E W D R A F T # 1 — C I S C O C O N F I D E N T I A L
Monitor the network and record the following statistics:
Step 4
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If faxes fail consistently, capture a copy of the voice settings by selecting Save As > Web page,
Step 5
complete from the administration web server page. You can send this configuration file to Technical
Support.
STEP 6
Note
Identify the type of fax machine connected to the ATA device.
Step 7
Contact technical support:
Step 8
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Silence Suppression and Comfort Noise Generation
Voice Activity Detection (VAD) with Silence Suppression is a means of increasing the number of calls
supported by the network by reducing the required bandwidth for a single call. VAD uses a sophisticated
algorithm to distinguish between speech and non-speech signals. Based on the current and past statistics,
the VAD algorithm decides whether or not speech is present. If the VAD algorithm decides speech is not
present, the silence suppression and comfort noise generation is activated. This is accomplished by
removing and not transmitting the natural silence that occurs in normal two-way connection. The IP
bandwidth is used only when someone is speaking. During the silent periods of a telephone call,
additional bandwidth is available for other voice calls or data traffic because the silence packets are not
being transmitted across the network.
Comfort Noise Generation provides artificially-generated background white noise (sounds), designed to
reassure callers that their calls are still connected during silent periods. If Comfort Noise Generation is
not used, the caller may think the call has been disconnected because of the "dead silence" periods
created by the VAD and Silence Suppression feature.
Silence suppression is configured in the Line and PSTN Line tabs. See

Configure Dial Plans

Dial plans determine how the digits are interpreted and transmitted. They also determine whether the
dialed number is accepted or rejected. You can use a dial plan to facilitate dialing or to block certain
types of calls such as long distance or international.
Cisco WRP500 Administration Guide
3-10
Jitter
Loss
Delay
Enable and capture the debug log. For instructions, refer to
You may also capture data using a sniffer trace.
If you are an end user of VoIP products, contact the reseller or Internet telephony service
provider (ITSP) that supplied the equipment.
If you are an authorized Cisco partner, contact Cisco technical support.
Chapter 3 Configure Voice Services
Appendix C, "Troubleshooting."
Appendix B, "Data Fields."