Chapter 3 Phone Use and Configuration

Note: Enter any advanced SIP configuration information as it was given to you by your SIP service provider. If you do not have any advanced configuration information, you can skip this section.

Figure 5 Advanced SIP Settings (part 1)

The following table describes the labels in this screen.

Table 2 SIP Setting

LABEL

DESCRIPTION

SIP Port

Enter the port number on your ZyXEL Device that SIP calls made with

 

the selected phone should use.

 

 

Media Port

Enter the port number on your ZyXEL Device that RTP media packets

 

should use.

 

 

Packetization

Select the voice codec packetization interval in milliseconds. The default

 

is 20 ms. This is used to minimize loss that happens during

 

transmission of voice data over the network.

 

The packetization interval effectivately sets the size of each voice

 

sample contained within a data packet. At 20 ms, the codec employed

 

in digitizing the voice signal can usually compensate for data

 

degredation and attenuation by using Packet Loss Concealment (PLC).

 

However, if the loss becomes too great, noticeable distortion occurs.

 

Setting the packetization interval higher, however, may introduce more

 

problems depending on the codec (such as G.711). Other codecs (such

 

as G.729 and G.723) have improved PLC techniques and as such can

 

also withstand a higher packetization interval; this means more packets

 

can be lost in transit without a noticeable loss in quality.

 

 

 

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P-27XX Series User’s Guide