DTMF Tone Parameters

The following table includes the parameters you can use to set up DTMF tones.

Table 1. DTMF Parameters

Template

Parameter

Permitted Values

Change Causes

Restart or Reboot

sip-interop.cfg

reg.1.telephony

1 (default) - Allows the phone to publish its capability in an SDP offer or answer to send and receive the DTMF tones over RFC-2833.

0 - Disables the phone's capability to send and receive the DTMF tones through RFC-2833 in an SDP offer or answer.

No

sip-interop.cfg

tone.dtmf.chassis.masking

0 (default) - DTMF tones play through the speakerphone in handsfree mode.

1 - Set to 1 only if tone.dtmf.viaRtp is set to 0. DTMF tones are substituted with non-DTMF pacifier tones when dialing in handsfree mode to prevent tones from broadcasting to surrounding telephony devices or inadvertently transmitted in-band due to local acoustic echo.

Yes

sip-interop.cfg

tone.dtmf.level

The level of the high frequency component of the DTMF digit measured in dBm0; the low frequency tone is two dB lower.

-15

-33 to 3

Yes

sip-interop.cfg

tone.dtmf.offTime

When a sequence of DTMF tones is played out automatically, specify the length of time in milliseconds the phone pauses between digits. This is also the minimum inter-digit time when dialing manually.

50 ms

Positive integer

Yes

sip-interop.cfg

tone.dtmf.onTime

Set the time in milliseconds DTMF tones play on the network when DTMF tones play automatically.

The time you set is also the minimum time the tone plays when manually dialing.

50 ms (default)

1 - 65535 ms

Yes

sip-interop.cfg

tone.dtmf.rfc2833Control

Specify if the phone uses RFC 2833 to encode DTMF tones.

1 (default) - The phone indicates a preference for encoding DTMF through RFC 2833 format in its Session Description Protocol (SDP) offers by showing support for the phone-event payload type. This does not affect SDP answers and always honor the DTMF format present in the offer.

Yes

sip-interop.cfg

tone.dtmf.rfc2833Payload

Specify the phone-event payload encoding in the dynamic range to be used in SDP offers.

Skype (default) - 101

Generic (default) -127

96 to 127

Yes

sip-interop.cfg tone.dtmf.rfc2833Payload_OPUS

Sets the DTMF payload required to use Opus codec.

126 (default)

96 - 127

Yes

sip-interop.cfg

tone.dtmf.viaRtp

1 (default) - Encode DTMF in the active RTP stream. Otherwise, DTMF may be encoded within the signaling protocol only when the protocol offers the option.

If you set this parameter to 0, you must set tone.dtmf.chassis.masking to 1.

Yes

sip-interop.cfg

tone.localDtmf.onTime

Set the time in milliseconds DTMF tones play for when the phone plays out a DTML tone sequence automatically.

50 ms (default)

1 - 65535 ms

No