N720 OpenLinux
Hardware User Guide
Copyright © Neoway Technology Co., Ltd
64
Incoming SMS
Upon receipt of an SMS message, the RING pin outputs a negative pulse of 35 ms.
Figure 3-58 RING indicator for SMS
35 ms
3.8.4 DTR
Signal
Pin
I/O
Function
Remarks
DTR
79
DI
Sleep mode control
DTR is the control pin of sleep mode. Send AT+ENPWRSAVE=1 to allow the module to enter sleep
mode and pull DTR low, then the module enters sleep mode.In sleep mode, the module can respond
to the incoming calls, SMS, and GPRS data.
The following figures show processes of entering sleep mode, service processes in sleep mode, and
process of exiting from sleep mode when an external MCU controls the module.
Figure 3-59 Process of entering sleep mode
<n>
0: Forbid sleep mode
1: Allow to enter sleep mode
Enter sleep mode at low level
Exit from sleep mode at high level
2: Allow to enter sleep mode
Enter sleep mode at high level
Exits from sleep mode at low level
Initialization
completed
AT+ENPWRSAVE=<n>
Whether the module
is in idle state
Pull SLEEP low
Enter sleep mode and
disable all interfaces
End
Processing current
services
Y
Y
N
DTR
