Cisco Small Business SPA509G Administration Manual page 146

Configuring Security, Quality, and Network Features
Configuring Voice Codecs
STEP 5
Cisco Small Business SPA300 Series, SPA500 Series, and WIP310 IP Phone Administration Guide
Parameter
DTMF Tx Method
DTMF Tx Volume
for AVT Packet
Use Remote Pref
Codec
Codec Negotiation
Click Submit All Changes.
Description
Select the method to transmit DTMF signals to the far end:
InBand, audio video transport (AVT), INFO, Auto, InBand+INFO,
or AVT+INFO. InBand sends DTMF using the audio path. AVT
sends DTMF as AVT events. INFO uses the SIP INFO method.
Auto uses InBand or AVT based on the outcome of codec
negotiation.
Defaults to Auto.
Allows you to manually configure the AVT Tx volume. The value
of this parameter is inserted into the volume field of the
payload in the AVT packet.
Values are based on the AVT specification as described in RFC
2833, RTP Payload for DTMF Digits, Telephony Tones and
Telephony Signals
. According to RFC 2833, the volume field is
represented by 6 bits, and describes the power level of the
tone, expressed in dBm0 after dropping the sign.
Valid range for this parameter is 0 to 63. If the provisioned
value is negative, it will be negated first. Thereafter, if the value
is beyond the high limit of 63, it will be clipped to 63.
The default value is 0, and is the recommended setting.
However, some gateways do not accept this volume setting. If
the gateway does not accept the value of 0, the DTMF tone is
not relayed to the remote end. As a workaround for the phone
to interoperate with those gateways, you can change the value
to a value greater than 0.
If set to yes, the phone communicates using the remote
phone's preferred codec. If set to no, the Cisco IP phone
communicates using its own preferred codec (as indicated in
the Preferred Codec field and in the SDP by order of
preferences). The default vale is no.
When set to Default, the Cisco IP phone responds to an Invite
with a 200 OK response advertising the preferred codec only.
When set to List All, the Cisco IP phone responds listing all the
codecs that the phone supports. The default value is Default,
or to respond with the preferred codec only.
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