Yealink SIP-T48G Administrator's Manual page 307

Parameters
Settings->Tones->Select Country
Phone User Interface:
None
voice.tone.dial
Description:
Customizes the dial tone.
tonelist = element[,element] [,element]...
Where
element = [!]Freq1[+Freq2][+Freq3][+Freq4] /Duration
Freq: the frequency of the tone (ranges from 200 to 7000 Hz). If it is set to 0Hz, it
means the tone is not played. A tone is comprised of at most four different
frequencies.
Duration: the duration (in milliseconds) of the dial tone, ranges from 0 to 30000ms.
You can configure at most eight different tones for one condition, and separate them
by commas. (e.g., 250/200, 0/1000, 200+300/500, 600+700+800+1000/2000).
If you want the IP phone to play tones once, add an exclamation mark "!" before
tones (e.g., !250/200, 0/1000, 200+300/500, 600+700+800+1000/2000).
Note: It works only if the parameter "voice.tone.country" is set to Custom.
Web User Interface:
Settings->Tones->Dial
Phone User Interface:
None
voice.tone.ring
Description:
Customizes the ringback tone.
The value format is Freq/Duration. For more information on the value format, refer to
the parameter "voice.tone.dial".
Note: It works only if the parameter "voice.tone.country" is set to Custom.
Web User Interface:
Settings->Tones->Ring Back
Phone User Interface:
None
Configuring Advanced Features
Permitted Values
String
String
Default
Blank
Blank
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