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5.2
Configuration of the bit rate on the serial interface
Please note that the module used in the terminal does not support autobauding. The configured data
rate is 115200 baud.
5.3
Power cycle the modem
There are two ways to switch off (power down) the modem as described below:
EMERG_OFF to high level for t >1s on the RJ11 connector
Turn off, or disconnect the power supply.
5.4
Using low power mode of the modem
The GT910 G terminal supports a special ultra-low power mode which can be activated or deactivated by
sending dedicated AT commands, which are described further below in this section. Please refer to
Section „2.4 Product Features and Technical Data” for detailed power consumption values.
Activating the low power mode can also deactivate the RS232 Transceiver, which helps further reduce
the power consumption. In some scenarios, however, this may not be desirable, as it may lead to data
loss. Therefore, the following preconditions for using the low power mode need to be considered:
•
There are no special precautions required when using a serial interface that is fully compliant
with the RS232 specification (V.24) both on the DTE and DCE. You can proceed as described in
the following sub-sections.
•
If the DTR line is not available on the DTE (the M2M application), and you do not need to use the
low power mode, then the DSR pin on DCE side should be looped with the DTR pin, as shown in
the figure below. With this approach, the ultra-low-power mode will be permanently disabled.
Figure 6: Looping the DSR with DTR pins to permanently deactivate low-power mode.
5.4.1
Enabling the low power mode
•
Wait until the GSM/GPRS module is logged onto the GSM/GPRS network
•
Send the AT command AT+CFUN=5 (section 3.5.4.4.2 of the AT command manual)
•
Set the DTR control line from High level to Low level
•
When the DTR line is Low, the user application is not ready to operate and the module enters
power saving mode
