Administrator’s Guide for SIP-T2 Series/T4 Series/T5 Series/CP920 IP Phones
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are using the phone handset or a headset.
Permitted
Values
Integer from 1 to 3
Default
2
Supported
Devices
T57W, T54W, T53W, T53, T48U, T46U, T43U, T42U
Smart Noise Filtering
The phones can block out the slight noise from the far party when there is no speech in a call, and at the same time
filter out the common transient noise (door closing, table knocking, and so on).
Topic
Smart Noise Filtering Configuration
Smart Noise Filtering Configuration
The following table lists the parameter you can use to configure smart noise filtering.
Parameter features.noise_filtering_rev.enable
<y0000000000xx>.cfg
Description
It enables or disables the phone to block out the slight noise from the far end when there is no speech
in a call.
Note: After smart noise filtering is enabled, if the far end is playing music or calling a voice service, the
background music will also be eliminated when there is no speech in a call.
Permitted
Values
0-Disabled
1-Enabled
Default
0
Supported
Devices
T57W, T54W, T53W, T53, T48U, T46U, T43U, T42U, CP920
Web UI
Settings > Voice > Smart Noise Filtering > Smart Noise Filtering
DTMF
DTMF (Dual Tone Multi-frequency) tone, better known as touch tone. DTMF is the signal sent from the IP phone to
the network, which is generated when pressing the IP phone’s 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.
Topics
DTMF Keypad
Transmitting DTMF Digit
Suppress DTMF Display
Transfer via DTMF
Local DTMF Tone
DTMF Keypad
The DTMF keypad is laid out in a 4×4 matrix, with each row representing a low frequency, and each column rep-
resenting a high frequency. Pressing a digit key (such as '1') will generate a sinusoidal tone for each of two fre-
quencies (697 and 1209 hertz (Hz)).
DTMF Keypad Frequencies:
