User manual

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3.2 Switch OFF the modem
The only way to turn off the modem is to remove power
3.3 Using low power mode of the modem
Below are some short descriptions on how to enter and exit the low power state of the modem.
3.3.1 Enabling the low power mode:
 wait until the GSM module is logged onto the GSM network
 send the AT command "AT+CFUN=9"
 set the RTS control line from High level to Low level
 after about 1-2 minutes, a stable low-power mode should be achieved
3.3.2 Disabling the low power mode by user:
 Set the RTS control line from Low to High
 Low-power mode should be exited automatically
 The RS-232 transceiver is activated immediately
 AT channel is available again after a short period of time (37ms)
 If applicable send AT command "AT+CFUN=1" to remain in normal mode
3.3.3 Disable the low power modes by incoming GSM activity:
 The RTS control line is still at a low level
 GSM module is called or receives an SMS
 Low-power mode is exited automatically
 RS-232 transceiver is activated immediately
 AT channel is available again after 37ms
 If activated by a call the text "ring" is transmitted via the serial interface
 The RTS control line on the DB-9 should be set from Low level to High level
 AT communication with the GSM module is now available
 If applicable send AT command "AT+CFUN =1" to remain in normal mode
3.4 Operating states / LEDs
3.4.1 Power up LED (green LED in the middle)
The modem has a green power up LED, as depicted below, which is used to indicate various
operating states. These states are described in following table.