ZyXEL Communications P-2602HW(L) Series - Manual (Page 164)

P-2602H(W)(L)-DxA Series User’s Guide
164 Chapter 11 Voice
11.11 Phone
You can configure the volume, echo cancellation and VAD settings for each individual phone
port on the ZyXEL Device. You can also select which SIP account to use for making outgoing
calls.
11.12 PSTN Line (“L” models only)
With PSTN line you can make and receive regular PSTN phone calls. Use a prefix number to
make a regular call. When the device does not have power, you can make regular calls without
dialing a prefix number.
Note: When the ZyXEL Device does not have power, only the phone connected to
the PHONE 1 port can be used for making calls. Ensure you know which phone
this is, so that in case of emergency you can make outgoing calls.
You can also use the PSTN Line screen to specify phone numbers that should always use the
regular phone service (without having to dial a prefix number). Do this for emergency
numbers (like those for contacting police, fire or emergency medical services).
11.12.1 Voice Activity Detection/Silence Suppression
Voice Activity Detection (VAD) detects whether or not speech is present. This lets the ZyXEL
Device reduce the bandwidth that a call uses by not transmitting “silent packets” when you are
not speaking.
11.12.2 Comfort Noise Generation
When using VAD, the ZyXEL 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.
11.12.3 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.
Apply Click this to save your changes and to apply them to the ZyXEL Device.
Cancel Click this to set every field in this screen to its last-saved value.
Table 56 SIP > QoS
LABEL DESCRIPTION