User's Manual

GE866-DUAL Hardware User Guide
1VV0301051 Rev. 2 – 2014-04-07 7
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Reserved. Page 18 of 82
Mod. 0805 2011-07 Rev.2
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.