ZyXEL Communications P-2602 manual Phone, Pstn Line L models only, Comfort Noise Generation

P-2602H(W)(L)-DxA Series User’s Guide

Table 56	SIP > QoS
LABEL		DESCRIPTION
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.

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.

164 Chapter 11 Voice