Cisco SPA501G Administration Guide - Page 136

Configuring Security, Quality, and Network Features Configuring Voice Codecs 5 Parameter Silence Supp Enable DTMF Tx Method DTMF Tx Volume for AVT Packet Description To enable silence suppression so that silent audio frames are not transmitted, select yes. Otherwise, select no. Defaults to no. The method for transmitting DTMF signals to the far end. The options are: InBand, audio video transport (AVT), INFO, Auto, InBand+INFO, or AVT+INFO. • InBand sends DTMF by 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 is negated first. Thereafter, if the value is beyond the high limit of 63, it is clipped to 63. The default value is 0 and the recommended setting. However, some gateways do not accept this volume setting. If the gateway does not accept a 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. Cisco Small Business SPA300 Series, SPA500 Series, and WIP310 IP Phone Administration Guide 135