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Each VoIP Bearer port can have up to seven individual Codecs configured under it. The Vocoder Profile object pane gives a user the ability to specify a codec or payload type such as G.711 ulaw etc. Maximum, Minimum, and Preferred payload types can also be modified through the drop down menu. Once created under the IP Profile object, the IMG 2020 IP signaling stacks will negotiate their use in the order in which they appear in the under the IP Profile object in the Web GUI. The priority with which the codecs are selected and utilized is determined by what position in the Web GUI tree the codec is positioned. If the codec is positioned at the top of the IP Profile codec list, it gets highest priority and the priority gets lower as the codec is positioned lower down the list. However, the priority of the codec can be changed by clicking on the codec icon in the configuration tree and dragging the codec up or down the IP Profile list of codecs. If a blue bar appears while moving the object, that indicates the object can be moved to that location. If a red circle with a line though it appears while moving the object, that indicates the object cannot be moved to that location. The screen capture just below displays a red circle with a line through it indicating the object could not be moved to that specific location in the Web GUI configuration tree.
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Related Topics and Dependencies
No dependencies.
Field Descriptions
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Codec | Description |
AMR | AMR is an audio data compression scheme for speech encoding. AMR is used in GSM and UMTS networks. AMR encodes narrowband signals at variable bit rates ranging from 4.75 to 12.2Kbps. (RFC 3267). |
AMR-WB | Refer to the topic for information on this codec. (RFC 3267). |
Clear Channel | Refer to the Clear Channel Codec Support topic for information on this codec. |
G711 alaw | Also known as PCM (Pulse Code Modulation). Has a 64 Kbps bitrate and is primarily utilized in most countries outside North America. |
G711 ulaw | Also known as PCM (Pulse Code Modulation). Has a 64 Kbps bitrate and is primarily utilized in North America. |
G723 5.3 Kbps | Standard speech codec which uses ADPCM. Transmits at 5.3Kbps. |
G723 6.3 Kbps | Standard speech codec which uses ADPCM. Transmits at 5.3Kbps. |
G729 | Audio data compression algorithm for voice. Used primarily in VoIP applications where bandwidth must be conserved. |
G722 | An ITU-T standard 7 kHz wideband speech codec operating at 48, 56 and 64 kbit/s. G.722 sample audio data at a rate of 16 kHz (using 14 bits), double that of traditional telephony interfaces, which results in superior audio quality and clarity. G722 64 bit is supported in BDN. |
iLBC 20ms | This is the Internet Low Bit-rate Codec which is approved as a standard codec by IETF as RFC 3951. It operates on 8 kHz speech frames of 20 ms corresponding to rates of 15.2 kbps. |
iLBC 30ms | This is the Internet Low Bit-rate Codec which is approved as a standard codec by IETF as RFC 3951. It operates on 8 kHz speech frames of 30 ms corresponding to rates of 13.3 kbps. |
GSM-FR Static Payload Type | A GSM full-rate wireless codec based on GSM 06.10 with a frame size of 20 ms and operates on 8 kHz speech. It is based on ETSI standards. The bit rate is 13.2 kbps. |
GSM-FR Dynamic Payload Type | Same as GSM-FR but supports a dynamic payload. |
G726-32/G721 Static Payload Type | G.726 is a standard voice codec which traditionally supports transmission rates of 16, 24, 32 or 40 kbit/sec. The IMG 2020 supports only the 32 kbit/sec rate which is optimal for voice transmission, and is also referred to as G.721. This codec uses a default static payload type of 2. |
G726-32/G721 Dynamic Payload Type | Same as G.726-32/G.721 but supports a dynamic payload type in the 96 - 127 range. |
GSM-EFR | GSM-EFR denotes the GSM 06.60 enhanced full-rate coding, specified in ETS 300 726. It has a frame size of 20 ms and operates on 8 kHz speech. The bit rate is 12.2 kbps. |
Refer to the SIP Codec Negotiation topic for payload size information on each of the codecs.
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