Dtmf - Yealink SIP-T48G Administrator's Manual

Microsoft Lync Edition Administrator's Guide for SIP-T2_Series and T4_Series IP Phones
2. Enter the desired characters in the Call Number Filter field.
3. Click Confirm to accept the change.
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 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.
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)).
DTMF Keypad Frequencies:
697 Hz
770 Hz
852 Hz
941 Hz
DTMF digits are transmitted using the RTP Event packets that are sent along with the
136
1209 Hz 1336 Hz
1 2
4 5
7 8
* 0
1447 Hz 1633 Hz
3 A
6 B
9 C
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