ZyXEL Communications P-2802H(W)(L)-I Series User Manual page 330

Chapter 26 Product Specifications
Table 148 Voice Features
Call waiting
Call forwarding
Caller ID
REN
Dynamic Jitter
Buffer
Multiple SIP
Accounts
Multiple Voice
Channels
Voice Activity
Detection/Silence
Suppression
Comfort Noise
Generation
Echo Cancellation
QoS (Quality of
Service)
SIP ALG
Other Voice
Features
330
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.
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.
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).
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.
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.
You can simultaneously use multiple voice (SIP) accounts and assign them to
one or both telephone ports.
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 (VAD) reduces the bandwidth that a call uses by not
transmitting when you are not speaking.
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).
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.
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.
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).
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)
P-2802H(W)(L)-I Series User's Guide