Sleep Mode 1 (At+Csclk=1); Wake Up Sim900-Ds From Sleep Mode 1 (At+Csclk=1); Sleep Mode 2 (At+Csclk=2) - SIM Tech SIMCom SIM900-DS Hardware Design

0: minimum functionality.
1: full functionality (default).
4: flight mode (disable RF function).
Minimum functionality mode minimizes the current consumption to the lowest level. If SIM900-DS 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 all AT commands correlative with RF function and SIM card function will not
be accessible.
For detailed information about the AT Command "AT+CFUN=<fun>", please refer to document [1].
Table 5: The Current consumption of Minimum Functionality Mode
<fun>
0
1
4
4.3.2

Sleep Mode 1 (AT+CSCLK=1)

User can control SIM900-DS module to enter or exit the sleep mode 1 (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),
SIM900-DS will enter sleep mode 1 automatically. In this mode, SIM900-DS can still receive paging or SMS
from network but the serial port is not accessible.
Note: For SIM900-DS, it requests to set AT command "AT+CSCLK=1" and ensure DTR at high level to enable the sleep mode 1;
the default value is 0, which can not make the module to enter sleep mode. For more details please refer to document [1].
4.3.3

Wake Up SIM900-DS from Sleep Mode 1 (AT+CSCLK=1)

When SIM900-DS 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.
4.3.4

Sleep Mode 2 (AT+CSCLK=2)

In this mode, SIM900-DS will continuously monitor the serial port data signal. When there is no data transfer over
5 seconds on the RXD signal and there is no on air and hardware interrupts (such as GPIO interrupt), SIM900-DS
will enter sleep mode 2 automatically. In this mode, SIM900-DS can still receive paging or SMS from network
but the serial port is not accessible.
Note: For SIM900-DS, It is requested to set AT command "AT+CSCLK=2" to enable the sleep mode 2; the default value is 0,
which can not make the module to enter sleep mode. For more details please refer to document [1].
SIM900-DS_Hardware Design_V1.00
Current consumption(uA) (sleep mode)
1030
1575
1100
22
Smart Machine Smart Decision
2013-01-20