User`s guide

User’s Guide
125
CHAPTER 12
The Phone Screens
12.1 Overview
Use the VOICE > Phone screens to configure the volume, echo cancellation, VAD settings
and custom tones for the phone port on the WiMAX Modem. You can also select which SIP
account to use for making outgoing calls.
12.1.1 What You Can Do in This Chapter
•The Analog Phone screen (Section 12.2 on page 126) lets you control which SIP accounts
each phone uses.
•The Common screen (
Section 12.3 on page 128) lets you activate and deactivate
immediate dialing.
•The Region screen (
Section 12.4 on page 129) lets you maintain settings that often depend
on the region of the world in which the WiMAX Modem is located.
12.1.2 What You Need to Know
The following terms and concepts may help as you read through this chapter.
Voice Activity Detection/Silence Suppression/Comfort Noise
Voice Activity Detection (VAD) detects whether or not speech is present. This lets the
WiMAX Modem reduce the bandwidth that a call uses by not transmitting “silent packets”
when you are not speaking.
When using VAD, the WiMAX Modem generates comfort noise when the other party is not
speaking. The comfort noise lets you know that the line is still connected as total silence could
easily be mistaken for a lost connection.
Echo Cancellation
G.168 is an ITU-T standard for eliminating the echo caused by the sound of your voice
reverberating in the telephone receiver while you talk.
Supplementary Phone Services Overview
Supplementary services such as call hold, call waiting, call transfer, etc. are generally
available from your VoIP service provider. The WiMAX Modem supports the following
services:
• Call Hold
• Call Waiting