Shanghai Simcom GSM/GPRS+GPS module : User's Manual : Page 25

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SIM868_Hardware_Design_V1.00 25 2016-06-20

4.3. Power Saving Mode

SIM868 has two power saving modes: Minimum functionality mode and sleep mode. AT command

“AT+CSCLK=1”can be used to set SIM868 into sleep mode. AT command “AT+CFUN=<fun>“can be used to

set SIM868 into minimum functionality. When SIM868 is in sleep mode and minimum functionality mode, the

current of module is lowest.

4.3.1. Minimum Functionality Mode

There are three functionality modes, which could be set by AT command “AT+CFUN=<fun>“. The command

provides the choice of the functionality levels <fun>=0, 1, 4.

 AT+CFUN=0： Minimum functionality.

 AT+CFUN=1： Full functionality (default).

 AT+CFUN=4： Flight mode (disable RF function).

Table 8: The current consumption of Function Mode

<fun>

BS-PA-MFRMS Current consumption(mA)

0 / 0.65

1

9 0.86

5 1.02

2 1.42

4 / 0.69

Minimum functionality mode minimizes the current consumption to the lowest level. If SIM868 is set to

minimum functionality by “AT+CFUN=0”, the RF function and SIM card function will be disabled. In this

case, the serial port is still accessible, but partial AT commands and correlative to RF function and SIM card

function will not be accessible.

For detailed information about AT command “AT+CFUN=<fun>“, please refer to document [1].

4.3.2. Sleep Mode 1 (AT+CSCLK=1)

Customer can control SIM868 module to enter or exit the sleep mode (AT+CSCLK=1) by DTR signal. When

DTR is in high level and without interrupt (on air and hardware such as GPIO interrupt or data in serial port),

SIM868 will enter sleep mode automatically. In this mode, SIM868 can still receive paging or SMS from

network but the serial port is not accessible.

4.3.3. Wake Up SIM868 from Sleep Mode 1

When SIM868 is in sleep mode 1(AT+CSCLK=1), the following methods can wake up the module:

 Pull down DTR pin.

The serial port will be active after DTR pin is pulled to low level for about 50ms.

 Receive a voice or data call from network.

 Receive a SMS from network.

 Receive external interrupt.

Note: After module has received incoming call or new SMS, serial port can report URC, but the serial port can

not input AT command. Only after the DTR pin is pulled to low level for 50ms, the serial port can input AT