This graphic illustrates what an overall VoIP solution looks like. On the left is the actual voice, which is either produced by the speaker or picked up by the microphone. This feeds into the analog codec, which is basically the analog-to-digital and digital-to-analog conversion that is done in an external audio codec. The information is then passed over the SSI interface to the processor, where the voice has to be either compressed or decompressed to limit the amount of network bandwidth that is necessary to transmit the voice information.