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VTech Communications LTD.
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Ref. No.: 20191009 Version: 01 Date: 09 Oct, 2019 Page 19 of 33
Figure 7-7 Speaker output
7.2.7 Mono operation
Mono operation is a single-channel operation of the stereo codec. The left channel represents the single mono channel for
audio in and audio out. In mono operation, the right channel is the auxiliary mono channel for dual-mono channel operation.
In single channel mono operation, disable the other channel to reduce power consumption.
7.2.8 Sidetone
In some applications, it is necessary to implement sidetone. This sidetone function applies configurable gain
to the microphone signal and feeds it into the DAC stream. The sidetone routing selects the version of the
microphone signal from before or after the digital gain in the ADC interface and adds it to the output signal
before or after the digital gain of the DAC interface, see Figure 7-8.