> 3.2.3 | Monitoring Power Supply by AT Command

> To monitor the supply voltage you can also use the AT^SBV command which returns the value related to the reference points BATT+ and GND.
> The module continuously measures the voltage at intervals depending on the operating mode of the RF interface. The duration of measuring ranges from 0.5s in TALK/DATA mode to 50s when TC65 is in IDLE mode or Limited Service (deregistered). The displayed voltage (in mV) is averaged over the last measuring period before the AT^SBV command was executed.