Common
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All Zoiper products support DTMF signaling.
What is DTMF?
This abbreviation stands for Dual-tone multi-frequency
The following definition for DTMF comes from Wikipedia
"DTMF signaling is used for telephone signaling over the line in the voice-frequency band to the call switching center. The version of DTMF used for telephone tone dialing is known by the trademarked term Touch-Tone, and is standardised by ITU-T Recommendation Q.23. Other multi-frequency systems are used for signaling internal to the telephone network."
Depending on the server setup, your VoIP provider might ask you to use a specific DTMF type.
Having the proper DTMF type is required for browsing voice menus, call parking, etc.
Supported characters:
DTMF supports the following characters:
* # 0 1 2 3 4 5 6 7 8 9 A B C D
It is not possible to send other characters as DTMF because of the traditional telephone system standards .
A, B, C and D keys are used rarely and exclusive for network control.
For example, the A key is used on some networks to cycle through different carriers at will.
Their use is probably prohibited by most carriers.
Supported DTMF types:
inband *
RFC2833
SIP INFO
* will only work reliably with alaw or ulaw audio codec.
Configuring what DTMF type to be used
in Zoiper for Windows Phone Mobile