> 6.4.2 | Call Handling and Internal Microphone Supply

> Because of voltage protection, the absolute maximum voltage on any MIC pin is limited. While the module is in an operating state with VMIC=off and inactive audio, the voltage at any MIC pin must not exceed ±0.3V relative to AGND, i.e., audio level 0.6Vpp (see [1]) otherwise undervoltage shutdown may be caused.
> Only if VMIC=on and active audio, the voltage applied to any MIC pin can be in the range of 2.4V to 0V with audio level of 1.6Vpp (full scale).
> To meet these requirements please ensure the appropriate control of voltage levels as well as of external microphone amplifiers or codec devices connected to MIC inputs.
> The following examples suggest a possible usage of VMIC control (AT^SNFM=,1):
> Figure 31: Example VMIC control for incoming call
> Figure 32: Example VMIC control for outgoing calls