User manual

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3.2 Switching OFF the modem
There are two ways to switch off (power down) the modem as described below:
 use the AT#SHDN command; DTR permanently to low (0,8V)
 HR_IN to high level for t > 5s
A delay of up to 10s is experienced as the modem logs off the network
3.3 Optional Low Power Mode
In addition to turning the device completely off the terminal can placed into a low power mode while
maintaining connectivity. To put the device into this low power mode the DTR line must be set to “low”
and the AT command “at+cfun=5” must be issued.
In the low power mode current consumption is approximately 10mA with a 12V supply.
There is an additional optional “low power” variant that is available on a project bases that can achieve
2mA with a 12V supply.
3.4 Operationg 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.
Operating state of HT910 Terminal
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
Not registered
Permanently on
Table 7: Operating states of the power up LED
3.4.2 Status LEDs (one yellow, one red)
The red and yellow Status LEDs are under control of GPIO1 and GPIO2 of the HT910 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 GPIO2 at#gpio=2,1,1
Switching off GPIO2 at#gpio=2,0,1
Switching on GPIO3 at#gpio=3,1,1