User manual

16
3.2 Switch OFF the modem
The only way to power off the modem is to remove power.
3.3 Operating states / LED
3.3.1 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.
Operating state of GT864 E
Power up LED state
Device off
Permanently off
net search / not registered /
Fast blinking (period=1s, LED
on
=0,5s
registered full service
Slow blinking (period=3s, LED
on
=0,3s
A call is active
Permanently on
Table 6: Operating states of the power up LED
3.3.2 Status LEDs (one yellow, one red)
The red and yellow Status LEDs are under control of GPIO1 and GPIO2 of the GT864 E modem
inside of the Terminal. They can be controlled via at-commands. The default status of these
two LEDs is off. The following commands have to be used to initialise and to configure the
GPIOs to control the two LEDs:
Switching on GPIO1 at#gpio=1,1,1
Switching off GPIO1 at#gpio=1,0,1
Switching on GPIO2 at#gpio=2,1,1
Switching off GPIO2 at#gpio=2,0,1
These LEDs can be controlled e.g. by an external microcontroller via at-commands issued to
the terminal via the serial RS232 interface. They can be used for signalling any useful status of
the external application such as:
 error indication
 status of communication (GPRS, SMS, CSD, etc.)
 status of GSM-network (to simulate GSM LED)
 quality of service