Transcoding Mode
By default, the device performs transcoding only when necessary. This refers to all types of transcoding (interworking) that require the use of the device's DSP resources, for example, voice coder transcoding, DTMF negotiations, and fax negotiations. Transcoding is required, for example, when two SIP entities use different coders. In such a scenario, the device can be configured to use a different coder for each leg (inbound and outbound), using IP Profiles. If the SIP entities use the same coder, the device doesn't perform transcoding.
Alternatively, you can configure the device to always perform transcoding, regardless of whether it is required or not. This is referred to as forced transcoding. For example, if the SIP entities use the same coder, the device performs transcoding of the same coder (e.g., G.711 and G.711) between the two legs.
To configure the transcoding mode, use the global parameter [TranscodingMode] or the IP Profile parameter 'Mediation Mode'.
If the transcoding mode is configured to Force Transcoding (i.e., always perform transcoding) for an IP Profile associated with a specific SIP entity, the device also applies forced transcoding for the SIP entity communicating with this SIP entity, regardless of its IP Profile settings.