CEP AG
Revision 1.2
_________________________________________________________________________________
__________________________________________________________________________________________
Page 14 of 28
All 3 cases above might prevent the modem from recognizing the power-up signal
this is no failure of the modem itself, the same would apply to almost any electronic
device that provides a separate “power-on” or “reset” signal.
If you are doubt, please
Use the mains power adapter that is provided by your distributor and is know
to work properly with your modem
Make sure that your signal and system design is according to the above
Consult our support team that will be more than happy to assist you.
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 1s < t < 2s
A delay of up to 10s is experienced as the modem logs off the network
3.3 Operating states / LEDs
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-QUAD/PY 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
A call is active
Permanently on
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-QUAD/PY 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
