Technical information

Chapter 2: Hardware Interface Description
November 15, 2008 G24-L Module Hardware Description 17
Low Power Mode
The G24-L incorporates an optional low power mode, called Sleep Mode, in which it operates in
minimum functionality, and therefore draws significantly less current. During low power mode
the G24-L network connection is not lost. G24-L continues to monitor the GSM network
constantly for any incoming calls or data.
During low power mode, all of the G24-L interface signals are inactive and are kept in their
previous state, prior to activating low power mode. To save power, all the G24-L internal clocks
and circuits are shut down, and therefore serial communications is limited.
Activating Low Power Mode
By default, the G24-L powers on in Idle mode. In this mode the G24-L interfaces and features are
functional and the module is fully active.
Low power mode is activated by the ATS24 command. The value set by this command
determines the inactive state duration required by G24-L, in seconds, after which G24-L will
enter sleep mode.
For example:
ATS24 = 1 activates low power mode after 1 second of inactivity.
ATS24 = 5 activates low power mode after 5 seconds of inactivity.
ATS24 = 0 disables low power mode (default).
Figure 2-7 illustrates the ATS24 command operation.
Figure 2-7: ATS24 Operation
Important: G24-L will not enter low power mode in any case when there is data present on the
serial interface or incoming from the GSM network or an internal system task is
running. Only when processing of any external or internal system task has
completed, and G24-L is inactive for the duration of ATS24, it will enter low power
mode.