ZyXEL p-2802h-i1 Manual Do Utilizador

Chapter 26 Product Specifications

P-2802H(W)(L)-I Series User’s Guide

Call waiting

This feature allows you to hear an alert when you are already using the phone 

and another person calls you. You can then either reject the new incoming call, 

put your current call on hold and receive the new incoming call, or end the 

current call and receive the new incoming call.

Call forwarding

With this feature, you can set the ZyXEL Device to forward calls to a specified 

number, either unconditionally (always), when your number is busy, or when 

you do not answer. You can also forward incoming calls from one specified 

number to another.

Caller ID

The ZyXEL Device supports caller ID, which allows you to see the originating 

number of an incoming call (on a phone with a suitable display).

REN

A Ringer Equivalence Number (REN) is used to determine the number of 

devices (like telephones or fax machines) that may be connected to the 

telephone line. Your device has a REN of three, so it can support three devices 

per telephone port.

Dynamic Jitter 

Buffer

The built-in adaptive buffer helps to smooth out the variations in delay (jitter) for 

voice traffic. This helps ensure good voice quality for your conversations.

Multiple SIP 

Accounts

You can simultaneously use multiple voice (SIP) accounts and assign them to 

one or both telephone ports.

Multiple Voice 

Channels

Your device can simultaneously handle multiple voice channels (telephone 

calls). Additionally you can answer an incoming phone call on a VoIP account, 

even while someone else is using the account for a phone call.

Voice Activity 

Detection/Silence 

Suppression

Voice Activity Detection (VAD) reduces the bandwidth that a call uses by not 

transmitting when you are not speaking. 

Comfort Noise 

Generation

Your device generates background noise to fill moments of silence when the 

other device in a call stops transmitting because the other party is not speaking 

(as total silence could easily be mistaken for a lost connection). 

Echo Cancellation 

You device supports G.168, an ITU-T standard for eliminating the echo caused 

by the sound of your voice reverberating in the telephone receiver while you 

talk.

QoS (Quality of 

Service) 

Quality of Service (QoS) mechanisms help to provide better service on a per-

flow basis. Your device supports Type of Service (ToS) tagging and 

Differentiated Services (DiffServ) tagging. This allows the device to tag voice 

frames so they can be prioritized over the network.

SIP ALG

Your device is a SIP Application Layer Gateway (ALG). It allows VoIP calls to 

pass through NAT for devices behind it (such as a SIP-based VoIP software 

application on a computer). 

Other Voice 

Features

SIP version 2 (Session Initiating Protocol RFC 3261)
SDP (Session Description Protocol RFC 2327)
RTP (RFC 1889)
RTCP (RFC 1890)
Voice codecs (coder/decoders) G.711, G.726,  G.729
Fax and data modem discrimination
DTMF Detection and Generation
DTMF: In-band and Out-band traffic (RFC 2833),(PCM), (SIP INFO) 
Point-to-point call establishment between two IADs 
Quick dialing through predefined phone book, which maps the phone dialing 

number and destination URL.
Flexible Dial Plan (RFC3525 section 7.1.14)

Table 148   Voice Features