ZyXEL Communications MAX-306, Руководство пользователя, Страница: 165 / 405

User’s Guide
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The Phone Screens
13.1 Overview
Use the VOICE > Phone screens to configure the volume, echo cancellation, VAD
settings and custom tones for the phone port on the WiMAX Device. You can also
select which SIP account to use for making outgoing calls.
13.1.1 What You Can Do in This Chapter
• The Analog Phone screen ( Section 13.2 on page 166 ) lets you control which
SIP accounts each phone uses.
• The Common screen ( Section 13.3 on page 169 ) lets you activate and
deactivate immediate dialing.
• The Region screen ( Section 13.4 on page 170 ) lets you maintain settings that
often depend on the region of the world in which the WiMAX Device is located.
13.1.2 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 Device reduce the bandwidth that a call uses by not transmitting
“silent packets” when you are not speaking.
When using VAD, the WiMAX Device 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.