Yealink VC400, Руководство администратора, Страница: 147 / 299

Configuring Call Preferences
131
Parameter Description Configuration Method
call other system using different
call types according the priority.
Default:
Disabled
To configure account polling via web user interface:
1.
Click on
Setting
->
Call Features
.
2.
Select the desired value from the pull-down list of
Account Polling
.
3.
Click
Confirm
to accept the change.
DTMF
DTMF (Dual Tone Multi-frequency), better known as touch-tone, is used for telecommunication
signaling over analog telephone lines in the voice-frequency band. DTMF is the signal sent from
the IP phone to the network, which is generated when pressing the keypad during a call. Each
key pressed on the IP phone generates one sinusoidal tone of two frequencies. One is
generated from a high frequency group and the other from a low frequency group.
The DTMF keypad is laid out in a 4×4 matrix, with each row representing a low frequency, and
each column representing a high frequency. Pressing a digit key (such as '1') will generate a
sinusoidal tone for each of two frequencies (697 and 1209 hertz (Hz)).