GT910 G Terminal
User Manual
Revision 1.0
2
Important information
This technical description contains important information for the installation and use of the
GT910 G terminal. Read it carefully before you start working with the GT910 G terminal.
We cannot be held responsible for material loss or personal injury that is due to non-compliance
with the safety instructions. The warranty will be void in such circumstances.
Telic reserves the right to change the included information without prior notice and does not
take responsibility for errors in the document and/or for any missing information.
3
Table of Contents
Important information ...................................................................................................................................................... 2
1 General Information ................................................................................................................................................. 6
1.1 Contact for Support .......................................................................................................................................... 6
1.2 Conventions Used in this Manual ..................................................................................................................... 6
1.3 Related Documentation .................................................................................................................................... 7
1.4 Abbreviations .................................................................................................................................................... 7
1.5 Revision History................................................................................................................................................. 8
2 Product Description .................................................................................................................................................. 9
2.1 Overview ........................................................................................................................................................... 9
2.2 Identification ................................................................................................................................................... 10
2.3 Physical Dimensions and Weight .................................................................................................................... 10
2.4 Product Features and Technical Data ............................................................................................................. 11
2.5 Telic Certified Accessories ............................................................................................................................... 13
3 Safety and Product Care ......................................................................................................................................... 15
3.1 Audience and Intended Use ............................................................................................................................ 15
3.2 Safety instructions .......................................................................................................................................... 15
3.3 General precautions ........................................................................................................................................ 16
3.4 SIM card precautions ...................................................................................................................................... 16
3.5 Antenna precautions ....................................................................................................................................... 17
3.6 Storage Conditions .......................................................................................................................................... 17
4 Electrical Description .............................................................................................................................................. 18
4.1 Power Connector ............................................................................................................................................ 18
4.2 Antenna Connector ......................................................................................................................................... 19
4.3 SIM card holder ............................................................................................................................................... 19
4.4 RS232 Serial Port ............................................................................................................................................. 19
4.4.1 Serial Data ............................................................................................................................................... 20
4.5 Mini USB Connector ........................................................................................................................................ 20
5 Operation ................................................................................................................................................................ 22
5.1 Switch ON the modem .................................................................................................................................... 22
5.2 Configuration of the bit rate on the serial interface ....................................................................................... 23
5.3 Power cycle the modem ................................................................................................................................. 23
4
5.4 Using low power mode of the modem ........................................................................................................... 23
5.4.1 Enabling the low power mode ................................................................................................................ 23
5.4.2 Disabling the low power mode by user .................................................................................................. 24
5.4.3 Disabling the low power mode upon receiving GSM activity ................................................................. 24
5.5 Operating states / green LED .......................................................................................................................... 24
5.6 Current consumption Measurements ............................................................................................................. 24
6 Installation of the modem ...................................................................................................................................... 26
6.1 Where to install the modem ........................................................................................................................... 26
6.1.1 Environmental conditions ....................................................................................................................... 26
6.1.2 GSM Signal strength ................................................................................................................................ 26
6.1.3 Connection of components to the GT910 G terminal ............................................................................. 26
6.1.4 Network and Subscription....................................................................................................................... 26
6.2 How to install the modem .............................................................................................................................. 26
6.2.1 Power supply ........................................................................................................................................... 26
6.2.2 Securing the modem ............................................................................................................................... 27
6.3 Antenna ........................................................................................................................................................... 27
6.3.1 General .................................................................................................................................................... 27
6.3.2 Antenna type ........................................................................................................................................... 27
6.3.3 Antenna placement ................................................................................................................................. 27
6.3.4 The antenna cable ................................................................................................................................... 27
6.3.5 Possible communications disturbances .................................................................................................. 28
5
Table Overview
Table 1: Abbreviation ........................................................................................................................................................ 7
Table 2: Documentation Change Log ................................................................................................................................ 8
Table 3: Feature Overview .............................................................................................................................................. 12
Table 4: Accessories List .................................................................................................................................................. 14
Table 5: RJ11 Pin and Signals Description ....................................................................................................................... 19
Table 6: Electrical characteristics of the serial port signals ............................................................................................ 20
Table 7: Operating states of the green LED .................................................................................................................... 24
Table 8: Power consumption in standby, idle and low power mode and active call...................................................... 25
Figure Overview
Figure 1: Connector on rear side of the Terminal ............................................................................................................. 9
Figure 2: Connectors on front side of the Terminal .......................................................................................................... 9
Figure 3: Drawing of the Terminal’s Housing .................................................................................................................. 11
Figure 4: RJ11 Pin Connector .......................................................................................................................................... 18
Figure 5: Mini USB Type A/B connector for GT910 G ..................................................................................................... 21
Figure 6: Looping the DSR with DTR pins to permanently deactivate low-power mode. .............................................. 23
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1 General Information
This User Manual consists of the following chapters:
Chapter
Description
1 General Information
provides basic information such as the conventions for the warnin
g
levels, applicable related documentations, used abbreviations, a revision history and
contact information.
2 Product Description
provides a brief overview about
the mechanical specification of the
product (including size and weight) as well as an overview of the functions and features
of the device as well as the available accessories.
3 Safety and Product Care
addresses the audience for this manual, the indented use of this
device and safety-related information important to read before using the device.
4 Electrical Des
cription
describes the electrical characteristics and pin allocation of the
device’s connectors.
5 O
peration
provides details relating to the commissioning of the device, including det
ails
on activating special features such as the low power mode.
6 Installation of the modem
provides important instructions about how to install the
device for the M2M application.
1.1 Contact for Support
Please submit your request to TELIC AG customer support using the following online form:
http://www.telic.de/en/support/support-request
Information about Telic AG, products and accessories, including FAQs, are available from the following
web site: http://www.telic.de.
1.2 Conventions Used in this Manual
The following conventions for warning levels are used in this manual:
Warning
Warnings against hazards that may result directly in serious injuries or death in case of non-
observance.
Caution
Warnings against hazards that may result in injuries in case of non-observance.
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NOTICE
Warnings against hazards that may result in material damage in case of non-observance.
Indicates that the device can be damaged by electrostatic discharge.
This note contains helpful suggestions or references to material not covered in the document.
1.3 Related Documentation
Please consult the download zone of the Telic AG website for additional documents related to GT910 G, such as
AT command manuals. Note that such type of documents can be accessed online only after you have registered
on our website and agreed with our terms of use. Please follow this link to register for a user account:
http://www.telic.de/en/nda-reg-form
Use the following link to login if you already have a valid user account:
http://www.telic.de/en/en-login
1.4 Abbreviations
Abbreviation Explanations
DCE Data Circuit Terminating Equipment
DTE Data Terminal Equipment
GPRS
General Packet Radio Service
GSM
Global System for Mobile Communication
ME Mobile Equipment
MO Mobile Originated
MS Mobile Station
PDU Protocol Data Unit
RF Radio Frequency
SIM Subscriber Identity Module
SMS Short Message Service
TA Terminal Adapter
TE Terminal Equipment
TS Telecom Services
Table 1: Abbreviation
8
1.5 Revision History
Revision Date Changes
1.0 23.02.2017 Initial version
Table 2: Documentation Change Log
9
2 Product Description
2.1 Overview
The pictures below show the mechanical design of the GT910 G terminal along with the positions of the
different connectors and mounting holes. The GT910 G terminal case is made of durable PC/ABS plastic.
Figure 1: Connector on rear side of the Terminal
Figure 2: Connectors on front side of the Terminal
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Please note the following:
The terminal can be securely fitted into your application by using the mounting holes positioned at the two
corners of the device.
The SIM card can be inserted into the modem without the need for any tools.
Section 4 Electrical Description“2. Electrical Description” describes the pins and electrical characteristics or
of the modem’s terminal’s various connectors are described in
Section 4.2 Antenna Connector“2.3 Antenna Connector” provides information about the antenna connector
is found in “2.3 Antenna Connector”
Special DIN Rail Mounting Brackets (Art-nr. 12304 or Art-nr. 12305) is available as an accessory
item which allows installation of the modem in industrial environments using DIN Rails. For
more details of our accessories please check chapter 2.5 Telic Certified Accessories.
2.2 Identification
On the bottom of the device, you will find the type label.
Label
Description
S/N
Serial number
1
Serial number
IMEI
International Mobile
Equipment Identity
FW
GSM firmware version
HW-Rev.
Hardware Revision
Number + Production date
Input
Supply Voltage Range
CE conformity mark
Disposal in accordance
with European Directive
2002/96/CE
2.3 Physical Dimensions and Weight
Overall dimensions: 77 x 67 x 26 mm
Weight: 91g
1
Note that the serial number consists of a 5-digit product ID followed by the device’s IMEI.
11
Figure 3: Drawing of the Terminal’s Housing
2.4 Product Features and Technical Data
NOTICE
Telic AG may, at any time and without notice, make changes or improvements to the products and
services offered and / or cease producing or commercializing them.
NOTICE – Optional Features
Features identified as “Optional” in this document are not assembled by default. Please contact our
Sales Team at http://www.telic.de/en/contact-us to clarify the details of ordering terminal variants.
Category Features Details
Air Interface
GSM/GPRS Frequency Bands 850 / 900 / 1800 / 1900 MHz
GPRS Class Class 10
GPRS Features
Mobile station class B
Coding scheme 1 to 4
PBCCH support
NACC, Extended TBF
Output Power
Class 4 (2W) for GSM850/GSM900
Class 1 (1W) for GSM1800/GSM1900
USSD Supported
SMS
Text and PDU mode, Cell Broadcast, SMS
over GPRS
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Additional Wireless Features DARP Support
Hardware Features
IP Protection IP 40
Memory 2 MB RAM / 5 MB Flash
SIM Card Holder 1x (1,8/3 Volt)
SIM Chip Option Assembly Option
LEDs 1 GSM
Type Approvals CE
Connectors
D-Sub (9-pin) 1x Female (RS232)
USB 1x Mini-USB (USB 2.0)
RJ11
1x Power + IOs (1x Analogue Input; 1x
Output)
FME 1x Male (Antenna)
Software
AT Command Set TS 27.005, 27.007 and Telit custom AT
Programming Language
Python
C APIs for Telic AppZone
Firmware Update Serial / FOTA
TCP/IP Stack Yes
Cellular Positioning Telit IoT Locate
Jamming Detection Yes
Power Management
Voltage Range 5V - 32V
Power Cons. (Idle Mode) typ. 19 mA @ 12V
Power Cons. (Low Power
Mode)
typ. 2 mA @ 12V
USB Host Powered Optional
Hardware Characteristics
Operating Temperature -30°C to +75°C
Dimensions 77x66x26 mm
Weight 91g
Table 3: Feature Overview
13
2.5 Telic Certified Accessories
Art-Nr. Description
Antennas
1202
0 Patch Antenna; FME female connector,
self-adhesive, waterproof, GSM: 900,
1800, 1900 MHz; UMTS: 2100 MHz
12021
Magnetic Antenna; FME female
connector, GSM: 900, 1800 MHz, UMTS:
2100 MHz
12019
Stub Antenna; FME female,
GSM:
900
,
1800 MHz; UMTS 2100 MHz
12016
Rectangular Antenna; FME
female,
GSM:
900, 1800 MHz; UMTS: 2100 MHz
12006
Roof-mount antenna; FME female
waterproof, 900, 1800, 1900, 2100, 2400
MHz
Others
12004
RS232 cable
(V.24 compliant)
; 1.5m for
PC connection
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12304
Mounting Bracket for DIN Rail; Terminal
Mounting bracket for DIN Rail
(rectangular)
12305
Mounting Bracket for DIN Rail; Terminal
Mounting bracket for DIN Rail (straight)
12002
Power supply 230V
AC / 12 VPC; 6pin
RJ11 connector
12003
Power
cable; 6pin RJ11 connector with
open ends; 1.5 m
12301
Mini USB cable
with open ends
~ 0.6 m
12302
USB-A to
Mini USB cable
;
1.0 m
Table 4: Accessories List
Please contact your distributor or Telic AG for availability or check Telic’s webpage http://www.telic.de.
15
3 Safety and Product Care
This device has been designed in accordance with industrial standards, manufactured with utmost care
using high-quality materials, and thoroughly tested. Nevertheless, its use may constitute a risk to persons
or cause material damage.
The following safety instructions must be followed to ensure the safety of users and of the device.
NOTICE
If these instructions are ignored, Telic AG will not assume responsibility for any damages that are
incurred. Telic AG may refuse warranty claims where evidence of product misuse is found.
Please read the information in this section and the information in Section 6 Installation of the modem before
starting your integration work!
3.1 Audience and Intended Use
This terminal product is targeted towards system integrators who need to add a wireless communications
link to their M2M / IoT application to capture data from the application as well as to remotely control
that application. Any other use is not intended.
3.2 Safety instructions
PLEASE READ THESE SAFETY INSTRUCTIONS AND KEEP A COPY OF THEM.
The GT910 G terminal contains highly integrated components which can be damaged by electrostatic
discharge if the user would open the housing.
Therefore, only touch the GT910 G terminal on the housing or connectors and avoid
touching the components on the board.
Always ensure that the use of the modem is permitted. The modem may present a hazard if used in the
proximity of personal medical electronic devices. As a rule, the modem must not be used in hospitals,
airports or planes.
Never use the modem at a gas station, refueling point, blasting area or in any other environment where
explosives may be present.
Operating the modem close to other electronic devices, such as antennas, television sets, and radios may
cause electromagnetic interference.
This product is intended to be used with the antenna or other radiating element at least 20 cm away from
any part of the human body. In applications where this rule cannot be applied, the application designer is
responsible for providing the SAR measurement test report and declaration.
You are responsible for observing your country's safety standards, and where applicable, the relevant wiring
rules.
16
Warning
When using products which are exposed to electric voltage the valid regulations have to be
observed.
Always make sure that the device is disconnected from the power supply before opening it.
You should only use tools on components, modules or devices if they are disconnected from the power
supply and the electric charge, which may still be stored in some components inside the device, has been
discharged.
All cables and wires which are energized and connected to the device, the module or components must
be checked regularly for any damage of the isolation shield or fractures of the cables. If the supply cables
are visibly damaged the device must be taken out of operation immediately until the faulty cable has
been replaced.
When using components or modules, the specification given in the corresponding description of these
components must strictly be observed. The device shall be operated only by appropriately qualified
personnel.
This device shall only be used for its intended purpose.
Please note that we are not responsible for any errors in usage of wireless connections. Therefore, we
cannot accept any responsibility for consequential loss.
In case measurements with the opened housing are necessary, an isolating-transformer must be
integrated for safety reasons. Alternatively, the voltage can be supplied by an appropriate power supply
which complies with the safety regulations. All wiring work must be done in a voltage free state only.
3.3 General precautions
The GT910 G terminal as a stand-alone item is designed for indoor use only. To use outside it must be
integrated into a weatherproof enclosure. Do not exceed the environmental and electrical limits as
specified in Section 2.4 Product Features and Technical Data.
Avoid exposing the modem to lighted cigarettes, naked flames or to extreme hot or cold temperatures.
Never try to dismantle the modem yourself. There are no components inside the modem that can be
serviced by the user. If you attempt to dismantle the modem, you will invalidate the warranty.
The GT910 G terminal must not be installed or located where the surface temperature of the plastic case
may exceed 80°C.
All cables connected to the GT910 G terminal must be secured or clamped, immediately adjacent to the
modem's connectors, to provide strain relief and to avoid transmitting excessive vibration to the modem in
the installation.
Ensure the cables, supplying power, and input cable to the GT910 G terminal do not exceed 3 meters.
To protect power supply cables and meet the fire safety requirements when the unit is powered from a
battery or a high current supply, connect a fast 1.25A fuse in line with the positive supply.
Do not connect any incompatible component or product to the GT910 G terminal.
3.4 SIM card precautions
Before handling the SIM card in your application, ensure that you are not charged with static electricity.
Use proper precautions to avoid electrostatic discharges.
17
When the SIM card hatch is opened, the SIM card connectors lie exposed under the SIM card holder.
Caution! Do not touch these connectors! If you do, you may release an electrical
discharge that could damage the modem or the SIM card.
When designing your application, the SIM card’s accessibility should be considered. We always
recommend that you have the SIM card protected by a PIN code. This will ensure that the SIM card cannot
be used by an unauthorized person.
3.5 Antenna precautions
Consider the risk of lightning in case the antenna is to be mounted outside. Follow the instructions
provided by the antenna manufacturer.
NOTICE
Please note that this GSM/GPRS device is designed for use with one single antenna only. It does not
support antenna diversity.
Never connect more than one modem to a single antenna. The modem can be damaged by radio frequency
energy from the transmitter of another modem.
Like any mobile station, the antenna of the modem emits radio frequency energy. To avoid EMI
(electromagnetic interference), you must determine whether the application itself, or equipment in the
application’s proximity, needs further protection against radio emission and the disturbances it might cause.
Protection is secured either by shielding the surrounding electronics or by moving the antenna away from
the electronics and the external signals cable.
The modem and antenna may be damaged if either come into contact with ground potentials other than
the one in your application. Beware, ground potential is not always what it appears to be.
3.6 Storage Conditions
The following environmental limits must be maintained in order to safely store the terminal and ensure
that it remains functional until a maximum of 12 months:
Storage temperature: from 5°C to 35°C
Humidity: <75% relative humidity.
18
4 Electrical Description
The modem uses the following standard connectors:
RJ11 6-way (power +IOs)
Mini USB (for data)
SIM card holder
FME male coaxial jack (antenna connector)
Sub-D female socket, 9 pin (RS232 serial port)
4.1 Power Connector
An RJ11 6-way connector, as shown and described below, serves as a means of supplying and controlling
DC power to the modem. The use of an external power supply is necessary as the USB port is not intended
to be used as power source.2
The supply voltage VCC required by the modem is 5V - 32V DC. Please note that applying the supply
voltage does not switch the modem on. To do so an additional active-high control signal, TO_IN, must be
applied for > 1 second.
Please see chapter 5.1 Switch ON the modem for further important details about TO_IN and power supply
requirements, especially if TO_IN is applied in parallel to VCC.
VCC and GND are reverse-polarity and over-voltage protected as long as the antenna
interface and the user’s application are not used or connected to separate grounds.
Figure 4: RJ11 Pin Connector
PIN Signal Direction Limits Description
1 VCC Input
5 – 32V Positive power input, DC
2 ADC_IN
Input
0-32V
Analogue Input
2
This Statement does not apply to the USB Host Powered version of the GT910 G.
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PIN Signal Direction Limits Description
3 EMERG_OFF
Input
5 – 32V Active high control line used to
switch off the terminal
V
IH
> 5V, V
IL
< .5V
Power off: t >1s
4 TO_IN
Input
5 – 32V Positive edge triggered signal;
used to switch on the modem
V
IH
> 5V, V
IL
< 0.5V
Power on: t >1s after VCC
available
VIH = Voltage Input high
VIL = Voltage Input low
5 DIG_OUT
Output
5 - VCC (Optional)
Digital Output
VCC,
max. 400 mA
6 GND Input
-
Negative power (ground) input
and return path for TO_IN and
EMERG_OFF
Table 5: RJ11 Pin and Signals Description
4.2 Antenna Connector
The antenna connector on the modem is assembled with an FME male coaxial jack. The customerselected antenna should fulfil the following requirements:
Frequency range: Depending on the frequency band(s) provided by the network operator, the customer
shall use the most suitable antenna for that/those band(s)
Bandwidth:
- 70 MHz in GSM 850
- 80 MHz in GSM 900
- 170 MHz in DCS Band
- 140 MHz in PCS Band
Impedance: 50 Ohm
Antenna Gain:
- GSM 850: < 6.43 dBi
- PCS 1900: < 2.75 dBi
Input Power: > 2 W
VSWR absolute max.: ≤ 10:1 (limit to avoid permanent damage)
VSWR recommended ≤ 2:1 (limit to fulfill all regulatory requirements)
Length of the antenna cable: <3m
4.3 SIM card holder
The Terminal is fitted with a SIM card holder designed for 1.8V and for 3V SIM cards. It is the flip-up type
which is lockable in the horizontal position and is accessed through a removable panel.
4.4 RS232 Serial Port
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The modem supports a standard RS232 serial interface via its 9 pin Sub-D connector, shown below. In
line with serial communication terminology the Terminal should be considered as the data circuitterminating equipment (DCE) and the external application or computer as the data terminating
equipment (DTE). The maximum data rate to communicate with the GT910 G terminal is 921,6 kBaud.
PIN Signal
Direction
Limits
Description
1 DCD Output
> + 4V
<- 4 V
Data carrier detect
2 RD Output
> + 4V
<- 4 V
Received data
3 TD
Input
> + 2,4V
< 0.8 V
Transmitted data
4 DTR Input
> + 4V
< 0.8 V
Data terminal ready
5 GND - 0 V Ground connection
6 DSR Output
> + 4V
< - 4 V
Data set ready
7 RTS Input
> + 2,4V
< 0.8 V
Request to send
8 CTS Output
> + 4V
< - 4 V
Clear to send
9 RI Output
> + 4V
< - 4 V
Ring indicator
Table 6: Electrical characteristics of the serial port signals
4.4.1 Serial Data
The modem supports the standard data character format of
Programmable baud rate
Auto-configuration mode with auto-baud.
4.5 Mini USB Connector
Figure 5: Mini USB Type A/B connector gives an overview about the PIN Assignment of the Mini USB
connector from the Standard GT910 G terminal.
The modem supports a standard USB 2.0 Full Speed slave interface to receive AT-commands as well as
data transmissions.
Drivers for Windows Desktop, Windows CE Embedded and instructions for Linux are available for
download from the Telic AG website (for registered users only).
21
Figure 5: Mini USB Type A/B connector for GT910 G
22
5 Operation
5.1 Switch ON the modem
NOTICE
To ensure correct operation of the Terminal, please ensure that a SIM Card has been inserted into the
terminal prior to switching it on.
Do not insert a SIM card into the device while it is switched on. If you find out that the device is switched
on but missing a SIM card, first switch off the modem and then insert the SIM card. Note that the device
does not have a SIM card detect feature.
There are two ways to switch on the modem, once power is applied:
assert TO_IN to high level for > 5s
activate the RS232 control line DTR for >0.2s
The modem is fully operational after 4 seconds. Logging onto a network may take longer than this and is
outside the control of the modem. The modem can be configured to start up at the time power is applied
by permanently tying power connector signals TO_IN (pin 4) and VCC (pin 1) together.
DTR must be cycled from low to high.
Although this will not be an issue in almost all typical applications of the modem, there are a few cases in which
the modem might not recognize 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.
Possible cases are the following:
Large capacitors in your power supply which will lead to slow leading and falling edges (issue does not apply
with modern stabilized switching regulator power-adaptors) AND TO_IN tied in parallel to VCC (instead of
separate dedicated digital signal)
Slow analogue signals used to assert TO_IN
TO_IN signal not before VCC
If you are in doubt, please
Use the mains power adapter that is provided by your distributor and is known 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.
The TO_IN signal requires a positive “edge” (a sharp” signal transition from low to high)
to turn the modem on. This transition should be a rising signal from 0V (GND) to VCC, or
at least a large fraction of that voltage range, and must be applied at the same time as
VCC or after it.
Very slow transitions (significantly slower than many milliseconds) or very small
transitions (e.g. only few volts instead of 0V to VCC) will not turn on the module (since
they are not considered to be a “positive edge”).
23
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
24
NOTICE
Enabling low power mode as described herein also deactivates the RS232 transceiver!
5.4.2 Disabling the low power mode by user
• Set the DTR control line from Low to High.
• Low-power mode should be exited automatically. After setting DTR from Low to High, the module
doesn’t save power, but the module is saving power again after setting DTR from High to Low.
• The RS232 transceiver is activated immediately.
• AT channel is available immediately after changing DTR from Low to High.
• Send AT command “AT+CFUN=1” to remain in normal mode.
5.4.3 Disabling the low power mode upon receiving GSM activity
• Pre-requisite: the RING line must be connected between DTE and DCE for this function to work.
The RING pin is used to indicate incoming SMS or calls.
• The DTR control line is still at a low level.
• GSM module is called or receives an SMS.
• Low-power mode should be exited automatically, if calling or sending an SMS to the GSM module.
NOTICE
The user must set DTR line to high in order to activate the RS232 transceiver, this is not done
automatically.
5.5 Operating states / green LED
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.
Default setting:
• Set alternate Timings: at#sled=4
• Safe configuration: at#sledsav
SLED = 2,50
Operating state of
GT910 G
Terminal
green
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)
Low power mode activated
Permanently o
ff
Table 7: Operating states of the green LED
5.6 Current consumption Measurements
The following table shows the typical power consumption of the Terminal in different modes.
25
[mA] @ 5V
[mA] @ 12V
[mA] @ 24V
[mA] @ 32
V
GT910 G
off (DTR low, no TO
-
IN)
0,1
0,1 0,2 0,3
GT910 G
idle mode (DTR
High, Creg=1)
4 20 16 11
GT910 G
low power mode
4 2 2 2
GT910 G
active call, PL=5
(TCH: 0124; MS Power:
33dBm)
241 104 57 45
GT910 G
active call, PL=12
(TCH: 0124; MS Power:
19dBm)
127 54 33 27
GT910 G
active call, PL=19
(TCH: 0124; MS Power:
5dBm)
101 44 28 24
Table 8: Power consumption in standby, idle and low power mode and active call
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6 Installation of the modem
This chapter gives you advice and helpful hints on how to integrate the GT910 G terminal into your
application from a hardware perspective. Please read the information given in Section 2 Product
Description and then read the information in this section before starting your integration work.
6.1 Where to install the modem
There are several conditions which need to be taken into consideration when designing your application
as they might affect the modem and its function. They are:
6.1.1 Environmental conditions
The modem must be installed so that the environmental conditions stated in Section 2.4 Product Features
and Technical Data, such as temperature, humidity and vibration are satisfied. Additionally, the electrical
specifications in Section 2.4 Product Features and Technical Data must not be exceeded.
6.1.2 GSM Signal strength
The modem has to be placed in a way that ensures sufficient GSM signal strength. To improve signal
strength, the antenna can be moved to another position. Signal strength may depend on how close the
modem is to a radio base station. You must ensure that the location at which you intend to use the
modem is within the network coverage area. Degradation in signal strength can be the result of a
disturbance from another source, for example an electronic device in the immediate vicinity. More
information about possible communication disturbances can be found in section 5.3.5.
When an application is completed, you can verify signal strength by issuing the AT command AT+CSQ.
See “AT + CSQ Signal Strength”.
Before installing the modem, use an ordinary mobile telephone to check a possible location for it. In
determining the location for the modem and antenna, you should consider signal strength as well as
cable length
6.1.3 Connection of components to the GT910 G terminal
The integrator is responsible for the final integrated system. Incorrectly designed or installed external
components may cause radiation limits to be exceeded. For instance, improperly made connections or
improperly installed antennas can disturb the network and lead to malfunctions in the modem or
equipment.
6.1.4 Network and Subscription
Before your application is used, you must ensure that your chosen network provides the necessary
telecommunication services. Contact your service provider to obtain the necessary information.
If you intend to use SMS in the application, ensure this is included in your (voice) subscription.
Consider the choice of the supplementary services
6.2 How to install the modem
6.2.1 Power supply
Use a high-quality power supply cable with low resistance. This ensures that the voltages at the connector
pins are within the allowed range, even during the maximum peak current.
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When the unit is powered from a battery or a high current supply, connect a fast 1.25A fuse in line with the
positive supply. This protects the power cabling and modem.
6.2.2 Securing the modem
Before securing the modem take into account the amount of additional space required for the mating
connectors and cables that will be used in the application.
Where access is restricted, it may be easier to connect all the cables to the modem prior to securing it in
the application.
Securely attach the GT910 G terminal modem to the host application using two 3mm diameter pan-head
screws.
6.3 Antenna
6.3.1 General
The antenna is the component in your system that maintains the radio link between the network and the
modem. Since the antenna transmits and receives electromagnetic energy, its efficient function will
depend on:
the type of antenna (for example, circular or directional);
the placement of the antenna;
Communication disturbances in the vicinity of the antenna.
The following sections address issues concerning antenna type, antenna placement, antenna cable, and
possible communication disturbances. In any event, you should contact your antenna manufacturer for
additional information concerning antenna type, cables, connectors, antenna placement, and the
surrounding area. You should also determine whether the antenna needs to be grounded or not. Your
antenna manufacturer might be able to design a special antenna suitable for the application.
6.3.2 Antenna type
Make sure that the selected antenna meets the requirements specified in Section 4.2 (“Antenna
Connector”).
6.3.3 Antenna placement
The antenna should be placed away from electronic devices or other antennas. The recommended
minimum distance between adjacent antennas, operating in a similar radio frequency band, is at least
50cm. If signal strength is weak, it is useful to face a directional antenna at the closest radio base station.
This can increase the strength of the signal received by the modem. The modem’s peak output power
can reach 2W. RF field strength varies with antenna type and distance. At 10cm from the antenna the
field strength may be up to 70V/m and at 1m it will have reduced to 7V/m. In general, CE-marked
products for residential and commercial areas, and light industry can withstand a minimum of 3V/m.
6.3.4 The antenna cable
Use 50Ω impedance low-loss cable and high-quality 50Ω impedance connectors (frequency range up to
2GHz) to avoid RF losses. Ensure that the antenna cable is as short as possible. The Voltage StandingWave Ratio (VSWR) may depend on the effectiveness of the antenna, cable and connectors. In addition,
if you use an adapter between the antenna cable and the antenna connector, it is crucial that the antenna
cable is a high-quality, low-loss cable. Minimize the use of extension cables, connectors and adapters.
Each additional cable, connector or adapter causes a loss of signal power.
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6.3.5 Possible communications disturbances
Possible communication disturbances include the following:
Noise can be caused by electronic devices and radio transmitters.
Path-loss occurs as the strength of the received signal steadily decreases in proportion to the distance from
the transmitter.
Shadowing is a form of environmental attenuation of radio signals caused by hills, buildings, trees or even
vehicles. This can be a particular problem inside buildings, especially if the walls are thick and reinforced.
Multi-path fading is a sudden decrease or increase in the signal strength. This is the result of interference
caused when direct and reflected signals reach the antenna simultaneously. Surfaces such as buildings,
streets, vehicles, etc., can reflect signals.
Hand-over occurs as you move from one cell to another in the GSM network. Your mobile application call is
transferred from one cell to the next. Hand-over can briefly interfere with communication and may cause a
delay, or at worst, a disruption.
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