ZyXEL Communications 2002 User Manual

P-2002 Series User’s Guide

64

Chapter 6 VoIP Screens

Quality of Service (QoS) refers to both a network's ability to deliver data with minimum delay, 
and the networking methods used to provide bandwidth for real-time multimedia applications. 

Network traffic can be classified by setting the ToS (Type Of Service) values at the data source 
(for example, at the Prestige) so a server can decide the best method of delivery, that is the 
least cost, fastest route and so on. 

DiffServ is a class of service (CoS) model that marks packets so that they receive specific per-
hop treatment at DiffServ-compliant network devices along the route based on the application 
types and traffic flow. Packets are marked with DiffServ Code Points (DSCPs) indicating the 
level of service desired. This allows the intermediary DiffServ-compliant network devices to 
handle the packets differently depending on the code points without the need to negotiate paths 
or remember state information for every flow. In addition, applications do not have to request 
a particular service or give advanced notice of where the traffic is going.

1

Fax Option

Use this field to set how the Prestige handles fax messages. You can select either 

the Fax Pass-through or the T.38 fax methods. 
Select Fax Pass-through to have the Prestige send fax messages over G.711. 

The peer devices must also use G.711. 
Select T.38 to have the Prestige send fax messages over the IP network as UDP or 

TCP/IP packets. It provides better transmission quality than fax pass-through but 

may have inter operability problems. The peer devices must also use T.38.

Call Forward Table Select which call forwarding table you want the Prestige to use to block or redirect 

calls. You can use a different call forwarding table for each SIP account or use the 

same call forwarding table for both.

Caller Ringing

Select the Enable check box to activate a custom caller ringing tone for incoming 

calls. The caller ringing tone is the sound that incoming callers will hear when they 

call you. Use the Caller Ringing Tone drop-down list box to choose a tone. 
The caller ringing tone currently works with calls that are using the G.729 codec.

On Hold

Select the Enable check box to activate a custom on hold tone for callers on hold. 

The on hold tone is the sound callers will hear when you put them on hold. Use the 

On Hold Tone drop-down list box to choose a tone.
The on hold tone currently works with calls that are using the G.729 codec.

Back

Click Back to return to the VoIP screen without saving configuration changes.

Apply

Click Apply to save your changes back to the Prestige.

Reset

Click Reset to begin configuring this screen afresh.

Table 14   VoIP Advanced (continued)

1.

The Prestige does not support DiffServ at the time of writing.