hello
UNDER-VOLTAGE WARNNING
If the voltage ≥ 4.3V, the following URC will be reported:
OVER-VOLTAGE WARNNING
If the voltage < 3.39V, the following URC will be reported, and the module will be automatically powered off.
maybe a mistake in the datasheet ?
OVER must be >
UNDER must be <
the reverse could be more easy to understand.
and when surge of comsuption of current , voltage decreases !
I am using a GSM QUECKETEL and had many problems, when using without external Battery 3,7V
because when the GSM exchange some data with MCU,
some spike of current appears and with a LM317 , maxi could be 1A max, not enough
maybe needs spike of 2 amps ..
so unexpectead reset of MCU occured.
The power supply of GSM is an important key to solve many problem.
The battery can supply, absorbe all spike of current needed by the GSM.