ZyXEL Communications P2000W 用户手册

P-2000W_V2 User’s Guide

102

Chapter 13 Administrator Web Configurator Screens

Table 20   PHONE 

Default Voice Codec A voice codec (coder/decoder) converts voice data to electrical signals for 

transmission over a network. 
Use this field to select the type of voice coder/decoder (codec) that you want the 

Prestige to use. Choosing a voice codec depends on a tradeoff between 

transmission speed, sound quality and desired bandwidth usage. G.711 provides 

higher voice quality than G.729 but requires 64kbps of bandwidth while G.729 

only requires 8kbps. The Prestige can only connect to other phones that use the 

same codec as the Prestige.
If you want to use G.711, G.711u is used mainly in North America and G.711a is 

used in most of the rest of the world.

Speaking Volume(-

14~14)

Select the default gain for the Prestige’s microphone, where –14 is the minimum 

(least sensitive) and 14 is the maximum (most responsive). 
The callee may hear an echo if you set the microphone’s volume to the 

maximum.

Listening Volume(-

14~14)

Select the default speaker volume on the Prestige, where –14 is the minimum 

(quietest) and 14 is the maximum (loudest).

RTP Port

Real time Transport Protocol is used to handle voice data transfer. Use this field 

to configure the Prestige’s listening port for RTP traffic. Leave this field set to the 

defaults if you were not given a RTP port to use.

Jitter Buffer

A larger receiving buffer allows the Prestige to rearrange data packets that arrive 

in the wrong order. 
Packets are dropped if they arrive out of order and the receiving buffer is full.
Increasing the buffer size introduces latency. Too large of a buffer could 

introduce a significant delay with a slow connection. Too small of a buffer may 

result in packets being lost. 

Voice Frames per 

Packet

Use smaller packet sizes to reduce the number of speech frames sent per 

packet. If a small packet does not reach its destination is it less significant than if 

the packet contained many speech frames. 

DTMF Relay

Dual Tone Multi-Frequency signals are generated when you press a key on the 

Keypad and communicate information (such as telephone numbers) to the VoIP 

gateway.  
Select disable to send the DTMF digits uncompressed from the remaining 

protocols to use a compression method to match that of your VoIP service 

provider’s.  
Select Inband(RFC 2833) to send the DTMF tones in RTP packets. 
Select Outband to send the DTMF tones in SIP messages.

DTMF Payload (0-

127)

This field allows you to set the DTMF payload type. It is recommended to leave 

the default setting for this field.

APPLY

Click APPLY to save your changes without restarting the Prestige. Your wireless 

LAN, Internet and SIP settings changes do not take affect until you use 

RESTART (in the navigation panel).

CANCEL

Click CANCEL to begin configuring this screen afresh.

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