GE866-QUAD Hardware User Guide
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Page 19 of 82
Mod. 0805 2011-07 Rev.2
NOTE:
The power supply must be applied either at the same time on pins VBATT and
VBATT_PA, or first applied on VBATT_PA and then on VBATT. The opposite sequence
shall be avoided. The reverse procedure applies for powering down the module: first
disconnect VBATT, then VBATT_PA, or both at once.
NOTE:
In order to prevent a back powering effect it is recommended to avoid having any
HIGH logic level signal applied to the digital pins of the GE866-QUAD when the
module is powered OFF or during an ON/OFF transition.
A flow chart showing the AT commands managing procedure is displayed below:
Modem ON Proc.
Disconnect PWR
supply
AT init sequence.
Delay 300mS
Enter AT<CR>
AT answer in
1second?
Y
N
Start AT CMD
.