iRZ ATM2-232 User manual

Table of Contents
1. Introduction.......................................................................................................................................................6
1.1. About this Document...................................................................................................................................6
1.2. Operating Instructions.................................................................................................................................6
1.3. Terms and Definitions .................................................................................................................................7
2. Product Overview...........................................................................................................................................10
2.1. Product Purpose and Main Functions.......................................................................................................10
2.2. Document Usage Procedure.....................................................................................................................11
2.3. Data Transfer Technology.........................................................................................................................11
2.4. Hardware Specifications ...........................................................................................................................11
2.5. Physical Specifications..............................................................................................................................12
2.6. Electrical Specifications ............................................................................................................................12
2.7. GSM Module Specifications......................................................................................................................13
2.8. Device Functional Circuit ..........................................................................................................................13
2.9. Device View...............................................................................................................................................14
2.10. Interfaces.................................................................................................................................................15
2.10.1. Mini USB Connector....................................................................................................................15
2.10.2. DB9 Connector (RS232)..............................................................................................................16
2.10.3. Power Connector.........................................................................................................................17
2.10.4. Terminal Connector (2GPIO+1GPO) ..........................................................................................18
2.11. The Modem Status Indication .................................................................................................................19
2.11.1. Signal Strength Indicators ...........................................................................................................19
2.12. Parameters and Attributes Used.............................................................................................................20
3. SIM Card Installation and Device Mounting ................................................................................................23
3.1. SIM Card Installation.................................................................................................................................23
3.2. Device Mounting........................................................................................................................................24
4. Device Operation Description.......................................................................................................................27
4.1. Modem Setup Preparation ........................................................................................................................27
4.2. Device Operating Procedure.....................................................................................................................28
4.3. Service Mode ............................................................................................................................................28
4.4. Offline Mode..............................................................................................................................................29
4.5. Updating Firmware....................................................................................................................................33

4.6. Setting Up the Modem ..............................................................................................................................34
4.7. Working with SIM Cards............................................................................................................................34
4.8. Working with the Server............................................................................................................................35
4.9. Working with the iRZ Collector Server......................................................................................................37
4.10. Encapsulation Mode................................................................................................................................38
4.11. Connecting to the Server via SMS Commands ......................................................................................39
4.12. Sending SMS on GPRS Connection Loss..............................................................................................39
4.13. Data Transmission via CSD....................................................................................................................40
4.14. Watchdog Timers....................................................................................................................................41
4.15. Real-Time Clock (RTC)...........................................................................................................................41
4.16. GPIO Pins Operation ..............................................................................................................................41
4.16.1. Setting Up Pins of the «Input» Type............................................................................................42
4.16.2. Setting Up Pins of the «Output» Type.........................................................................................43
4.16.3. GPIO Pins Control via SMS Commands.....................................................................................45
4.17. Operating with Incoming SMS Messages...............................................................................................46
4.18. Modem Operation in the Server Mode....................................................................................................46
4.18.1. Authentication of Connecting Clients ..........................................................................................47
4.18.2. Monitoring and Control via iRZ Collector.....................................................................................48
4.18.3. TCP/IP Connection Control.........................................................................................................49
4.18.4. SMS on IP Address Change .......................................................................................................49
5. Log Main Messages .......................................................................................................................................50
5.1. Log Messages at the Modem Activation...................................................................................................50
5.2. Log Messages on the SIM Cards Used ....................................................................................................51
5.3. Log Messages at the Operation with Servers...........................................................................................52
5.4. Log Messages at Sending SMS on GPRS Connection Loss ...................................................................53
5.5. Log Messages at Receiving Signals from Outputs...................................................................................53
5.6. Log Messages at Receiving SMS Commands by the Modem..................................................................54
6. Contacts and Support....................................................................................................................................55

List of Tables
Table 2.1 DB9 connector pin assignments...............................................................................................................16
Table 2.2 Power connector pin assignments............................................................................................................18
Table 2.3 Terminal connector pin assignments........................................................................................................18
Table 2.4 LED indication signals...............................................................................................................................19
Table 4.1 Assignments of pins set to input...............................................................................................................42
Table 4.2 Output operation algorithm .......................................................................................................................43
Table 4.3 Available types of signals in the command mode.....................................................................................44
Table 5.1 The sample of start log content ................................................................................................................50
Table 5.2 The sample of log messages at the module activation.............................................................................51
Table 5.3 The sample of log messages on SIM cards used.....................................................................................52
Table 5.4 The sample of log messages at operation with servers ...........................................................................52
Table 5.5 The sample of log messages at sending SMS messages on GPRS connection error ............................53
Table 5.6 The sample of log messages at receiving signals from pins....................................................................53
Table 5.7 The sample of log messages at receiving SMS commands by the modem.............................................54
List of Images
Fig. 1.1 Interaction diagram when using the iRZ Collector software solution –the modem operates in a client mode
.....................................................................................................................................................................................8
Fig. 1.2 Interaction diagram when using the iRZ Collector software solution –the modem operates in a server
mode............................................................................................................................................................................8
Fig. 2.1 ATM functional diagram...............................................................................................................................14
Fig. 2.2 Front Panel ..................................................................................................................................................14
Fig. 2.3 Back Panel...................................................................................................................................................15
Fig. 2.4 Mini USB connector .....................................................................................................................................16
Fig. 2.5 DB9 connector .............................................................................................................................................16
Fig. 2.6 Power connector..........................................................................................................................................18
Fig. 2.8 Signal strength indicators (a sample for the CSQ signal strength from 16 to 19) .......................................20
Fig. 3.1 Removing the SIM card tray from the modem.............................................................................................23
Fig. 3.2 Inserting the SIM card into the tray..............................................................................................................24
Fig. 3.3 The АТМ modem drawing dimensions ........................................................................................................25
Fig. 3.4 Device mounting –mounting the modem on a DIN rail to the side panel ...................................................25

Fig. 3.5 Device mounting –mounting the modem on a DIN rail with the front panel facing up................................26
Fig. 3.6 Device mounting –mounting the modem on the wall..................................................................................26
Fig. 4.1 Procedure of selecting a production server .................................................................................................36
Fig. 4.2 The diagram of operation with one server without backup..........................................................................36
Fig. 4.3 The diagram of operation with two servers..................................................................................................37
Fig. 4.4 The diagram of operation with two IP addresses on one server .................................................................37
Fig. 4.5 Methods of remote access to the modem....................................................................................................46
Fig. 4.6 Types of client authentication at connection to the modem-server .............................................................47
Fig. 4.7 The interaction diagram when using the iRZ Collector software solution - the modem operates in the
server mode...............................................................................................................................................................49

1. Introduction
1.1. About this Document
The document contains description and operating procedure of the iRZ ATM2-232 GSM/GPRS modem (he-
reinafter referred to as ATM). The document is intended for the users who are in charge of configuration and
maintenance of systems where data is transmitted via this device.
Document version
Firmware Version
Hardware Version
Issue Date
3.8
11.08
02
12.03.2015
Written by
Y. Petrova, P. Malikova
Approved by
D. Pavlov, G. Samakova
See also:
on getting started with the ATM Control utility and the modem basic setup –the «Setting Up iRZ ATM
Step by Step. ATM Control»document;
on setting up the modem via ATM Control –the «User Guide on the ATM Control Modem Configuration
Utility»document;
on setting up the modem via AT commands –the «AT Commands to Set Up the iRZ ATM2-232 Mod-
em»document;
on the benefits of the specialized iRZ Collector server –the «iRZ Collector. Solution Overview»
document;
on the use of the iRZ Collector dispatching application –the «iRZ Collector Dispatching Software Setup
and Operation User Guide»document.
1.2. Operating Instructions
The modem can interfere with electronic devices, therefore there are the following limitations on its use:
Power off the modem in medical centres and keep it away from medical equipment (for example, cardiac
pacemakers, and hearing aids).
Power off the modem in aircraft, take measures against accidental switch-on.
Power off the modem near gas stations, enterprises of chemical industry, in areas where blasting operations
are in progress.
At close range the modem can interfere with television and radioreceiver operation.
To ensure safe operation, follow the recommendations:
Do not expose the modem to aggressive influences (high temperatures, corrosive chemicals, dust, water,
etc.).

Protect the modem from impacts, drops and extreme vibration.
Do not attempt to disassemble or modify the modem. Such actions will void the warranty.
Note! Use the device in compliance with the operating instructions. The end user shall have no coverage
or benefits under the warranty if the product has been subject to abnormal use and storage.
1.3. Terms and Definitions
Local configuration or firmware updating –configuration or updating of the modem firmware connected to a
computer via a USB cable. For the ATM modem they are performed via the ATM Control program.
Remote configuration or firmware updating –configuration or updating of the modem firmware located on
the site, from the dispatching center. For the ATM modem they are performed via the iRZ Collector dispatching
application which is used together with the iRZ Collector server application.
Modem-client –the ATM modem operating in the TCP/IP client mode, i.e. the modem is connected to the data
collection server and transmits it data from an external device.
Modem-server –the ATM modem operating in the server mode, i.e. the modem awaits incoming connections
and processes them.
The system of data collection and device control (hereinafter referred to as system) –a set of tools for
automated data collection from external devices, located on sites, and their control as well as its processing, ac-
cumulation and transmission.
Server –a computer or specialized computer equipment with the installed server software for processing client
requests (in the terms of a client-server interaction model).
iRZ Collector solution –iRZ-manufactured software solution including the server and the dispatching applica-
tions of iRZ Collector.
iRZ Collector server application –the iRZ Collector server software to be installed on a data collection server.
It enables a third-party polling software, acting as a client (in the terms of a client-server interaction model), to re-
ceive data from the modems, which also act as a client. That is, the server application serves as a kind of «layer»
enabling their interaction (see Fig. 1.1).

For ease of reference, hereinafter the server with the installed iRZ Collector server application is referred as the
iRZ Collector server.
In case when the ATM modem operates in the server mode, it accepts connections itself: it no longer requires a
broker to interact with the polling software, operating in a client mode. In this case the iRZ Collector solution can
be still used to monitor and control the system modems (see Fig. 1.2).
Fig. 1.1 Interaction diagram when using the iRZ Collector software solution –the modem operates in a client mode
Fig. 1.2 Interaction diagram when using the iRZ Collector software solution –the modem operates in a server
mode
The iRZ Collector dispatching application –the iRZ Collector dispatching software which operates together
with the iRZ Collector server application and enables remote monitoring and control of the system modems. It can
be used in the dispatching center or data collection server as well as in any computer with the operating system
supporting the application.
External devices polling software is used in the dispatching center to poll external devices and is provided by
their manufacturer. Generally, it operates in the client mode, and therefore the following two methods are used to
interact with the modem: First –the modem operates in the client mode, and a special-purpose «layer»(for exam-
ple, the iRZ Collector server application) is used to interact with it. Second –the modem operates in the server
mode that enables a third-party software to connect it directly.

However in the second case each modem requires an external1static IP address.
Dispatching center –data collection and dispatching center intended to poll external devices, installed on
sites, and to monitor and control the system modems.
Data collection server2–the server where all the system data is accumulated and processed: data from ex-
ternal devices and system service information. The modem-clients are connected to the data collection server
and transmit the required data, the external device polling software is also connected to the server and re-
quests the data received by the server from the modem.
External device –the device mounted on a site and connected to the modem via the RS232 communica-
tions interface. Heat and energy meters, as well as any systems of telemetry and telemechanics, may act as
external devices.
SMS command –an SMS message sent to the modem, containing a character-based command of a certain
format.
1If your company rents an access point (APN) from a mobile network carrier, the modem will use an internal static ad-
2Used if the modem and the external devices polling software operate as clients. If the modem operates in the server
mode, the software can be connected to it directly and read out the required data.

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2. Product Overview
2.1. Product Purpose and Main Functions
The iRZ ATM GSM/GPRS modem provides data transmission over GPRS via TCP/IP protocol stack.
The device is designed for operation in telemetry systems.
The modem can operate in any of the three modes: client, server or CSD only. In the Client mode (hereinaf-
ter –modem-client) the modem is connected to the data collection server and transmits data from an external
device. In the Server mode (hereinafter –modem server), the modem, on the contrary, waits for the client in-
coming connection (for example, from a dispatcher computer) on a certain port and processes it. In the CSD
only mode data is transmitted via CSD (voice channel) with no data transmission over GPRS and the offline
mode available.
For operation in the Client mode you can use any SIM card, for operation in the Server mode it is recom-
mended to use a SIM card with an external1static IP address. For operation in the CSD only mode you can
use any CSD-enabled SIM card.
In the Client and Server modes the modem automatically connects to GPRS. After that the modem estab-
lishes connection to the specified server (if operating in the client mode) or opens an incoming port and waits
for incoming connections (if operating in the server mode).
The device provides transparent communication between a third-party external devices polling software and
an external device connected to the modem via RS232 interface. The modem tracks the GPRS connection sta-
tus and in case of connection loss, the modem restores it (see section «Device Operating Procedure»)
The ATM modem allows for the use of two SIM cards providing backup mobile communication (see section
«Working with SIM Cards»).
The client mode supports backup Internet connection –the main server switches to a backup server in case
of disconnection. Switching between servers is also available by a signal from the modem GPIO pins (see sec-
tion «Working with the Server»).
The modem-client can operate with a standard server (see section «Working with the Server») or a special-
purpose iRZ Collector server. The iRZ Collector server provides transparent data communication between a
third-party polling software, operating as a client, and the modems which also operate as clients and do not
have static IP addresses (see section «Working with the Server»).
The modem supports data transmission over CSD (voice channel). If there are phone numbers enabled in
the modem settings, data transmission over CSD is available in the client and server mode. In addition, ATM
supports a separate mode for data transmission only over CSD.
1If your company rents an access point (APN) from a mobile network carrier, addresses of the sites for such network
will be internal. In this case it is recommended to use a private static address.

11
The modem has additional pins (GPIOs) to monitor and control external devices (see section «GPIO Pins
Operation»). ATM can send SMS messages at change of pin signal strength enabling remote control of ex-
ternal devices connected to the modem. The pins state can be changed by sending SMS command to the
modem enabling remote control of external devices.
The modem features the offline mode supporting all functions except GPRS connection (see section
«Offline Mode»). Offline mode provides economy of traffic and power consumption. It is used if there is no
need for continuous connection.
ATM tracks the GSM module hangup and provides its additional restart by a signal from the configurable
watchdog timer (see section «Watchdog Timers»). The modem provides operation within a wide range of in-
put voltages and temperatures.
During its operation the modem displays messages in the log via USB interface in a real time. To view
and analyze the log on a computer, use any terminal program (see section «Log Main Messages»).
2.2. Document Usage Procedure
The modem functionality, described in sections «Service Mode», «Offline Mode», «Updating Firmware»,
«Setting Up the Modem», «Working with SIM Cards», «Connecting to the Server via SMS Commands»,
«Sending SMS on GPRS Connection Loss», «Data Transmission via CSD», «Watchdog Timers», «Real-Time
Clock (RTC)», «GPIO Pins Operation», «Operating with Incoming SMS Messages», refer both to the Client
and Server modes. In cases when the action of a function depends on the modem operating mode, it is speci-
fied directly in the function description.
Sections «Working with the Server»and «Working with the iRZ Collector Server»refer only to the Client
mode, section «Modem Operation in the Server Mode»—only to the Server mode.
In the CSD only mode the modem cannot operate as a client or a server, data can be transmitted only
over CSD. The CSD only mode does not support: GPRS connection (including operation with the server), of-
fline mode, remote firmware updating and settings change as well as the Modbus protocol for a COM port.
Other features are supported in the same way as for the Client and Server modes.
2.3. Data Transfer Technology
The ATM GSM/GPRS modem supports the following data transmission technologies:
GPRS;
CSD;
SMS.
2.4. Hardware Specifications
ATM has the following hardware specifications:

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GSM/GPRS module –BGS2;
Mini USB for setting up and logging the modem operation;
dual SIM card support;
antenna connector –SMA;
communication connector –RS232;
power connector –MicroFit 4;
terminal connector –2 GPIO + 1 GPO.
2.5. Physical Specifications
ATM has the following physical specifications:
housing dimensions (without connectors) –max 66 × 83 × 25 mm (L × W × D);
product dimensions (with connectors) –max 74 × 83 × 25 mm (L × W × D);
product weight –not exceeding 120 g;
operating temperature: -40°С to +65°С;
storage temperature: -50°С to +85°С;
permissible humidity –the device ensures safe operation at relative humidity of maximum 80% at 25°С.
2.6. Electrical Specifications
Power supply:
power voltage 7 to 40 V (DC);
current consumption in GPRS mode, max:
at power voltage of +12 V –250 mA;
at power voltage of +24 V –125 mA;
current consumption in the offline mode, max:
at power voltage of +12 V –60 mA;
at power voltage of +24 V –30 mA.
GPIO 1 and 2 in the “input”mode:
resistance of the programmable pullup to power voltage –10 kΩ;
resistance of the programmable pullup to ground –47 kΩ;
maximum voltage of level “0”(low level) –0.8V;
minimum voltage of level “1”(high level) –2.0V;
maximum allowable input voltage –40V.
GPIO 2 in the “input” mode set to ADC:

13
current measurement parameters:
current measurement range, mA: 0 to 30;
current measurement error, mA: 0.2.
voltage measurement parameters:
voltage measurement range, V: 0 to 40;
voltage measurement error, V: 0,2.
GPIO 1 and 2 in the “output”mode:
output type –open collector to ground;
output resistance –120 Ω;
maximum output current –10 mА.
GPO 3 in the «output»mode:
output type –open collector to power voltage;
output resistance –max 2 Ω;
maximum output current –500 mА.
2.7. GSM Module Specifications
Bandwidth:
900/1800 MHz;
850/900/1800/1900 MHz (optional).
Transmitter output power:
at frequency of 850/900 MHz —2 W;
at frequency of 1800/1900 MHz —1 W.
2.8. Device Functional Circuit
The modem main components:
power connector;
voltage converter;
GSM module;
SMA connector for external antenna;
microcontroller (MC);
mini USB;
RTC module battery;
9-pin RS232 (DB-9);
4-pin terminal connector (GPIO);
SIM1 and SIM2 holders (SIM1 and SIM2);

14
an operating SIM selection module (SIM selection);
LEDs;
hard reset and signal strength detection button (Firmware key).
Fig. 2.1 ATM functional diagram
2.9. Device View
The device view is given in Fig. 2.2 and Fig. 2.3:
Fig. 2.2 Front Panel

15
Fig. 2.3 Back Panel
Numbers in Fig. 2.2 and Fig. 2.3 illustrate:
1. mini USB connector;
2. SIM 1 tray (SIM 1);
3. SIM 1 tray eject button (SIM 1);
4. SIM 2 tray (SIM 2);
5. SIM 2 tray eject button (SIM 2);
6. SIM 1 LED indication (SIM 1);
7. SIM 2 LED indication (SIM 2);
8. antenna connector;
9. terminal connector (2 GPIO + 1 GPO);
10. DB9 connector (RS232);
11. MicroFit 4 power connector;
12. hard reset and signal strength detection button.
2.10. Interfaces
The device is equipped with two serial interfaces: Mini USB and RS232 as well as the GPIO programmable
interface.
2.10.1. Mini USB Connector
The mini USB interface is used to set up the modem and log its operation (log removal). For operation of the
modem via Mini USB, it is required to install the USB driver which can be downloaded from the official website
of the Radiofid Group of Companies (www.radiofid.ru) in section «Support». The computer determines the

16
modem as a virtual COM port. The modem is powered via Mini USB interface only for operation in the service
mode.
Fig. 2.4 Mini USB connector
Note 1. USB is used in the «device»mode, therefore it can be used only for connection to a computer or
other host controller.
Note 2. With a terminal program, for example, Hyper Terminal, close a COM port in this program before
you connect a USB cable. After that, connect the USB cable.
Then open the COM port.
2.10.2. DB9 Connector (RS232)
The connector is used to connect the modem to an external device with the RS232 interface (COM port).
Port factory settings: baud rate –9600, data bits –8, parity –not used, stop bits –1. All the parameters of the
operating COM port are changed in the service mode.
Fig. 2.5 DB9 connector
Table 2.1 DB9 connector pin assignments
Pin
Signal
Direction
Assignment
1
DCD
Modem –device
Carrier Detect

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Pin
Signal
Direction
Assignment
2
RXD
Modem –device
Receive Data
3
TXD
Device –modem
Transmit Data
4
DTR
Device –modem
Data Terminal Ready
5
GND
–
Ground. Connected to the negative
terminal of the power supply
6
DSR
Modem –device
Data Set Ready
7
RTS
Device –modem
Request To Send
8
CTS
Modem –device
Clear To Send
9
RI
Modem –device
Ring Indicator
Important!The RS232 (COM port) standard does not allow hot plugging. To prevent damage to the
COM port, wait at least 5 seconds to plug and unplug connected devices after turning off power.
The DCD, DSR, CTS, RING pins can be set to a high or low state in the encapsulation mode (see section
4.10 «Encapsulation Mode») or in the service mode using the ATM Control application. By default, the DCD,
DSR, CTS pins are set to a high state, RING –to a low state.
The modem supports operation with the COM port via the Modbus protocol. There are two protocol imple-
mentations available –Modbus RTU and Modbus ASCII.
Modbus RTU is a packet switching protocol used for operation with external devices via the RS232, RS485
and RS422 interfaces. When operating in the GPRS network, overload of base stations might cause data link
failure. The modem operating with Modbus RTU prevents data link failure (over 1.5 times character length), i.e.
the modem task is to transmit a single data packet over the RS-232/RS-422/RS-485 interfaces. The Pause op-
tion allows the user to manually set the time interval of data absence, which will enable the modem to identify
the end of data packet. Modbus RTU is required especially if it used to operate in an external device.
Specify the Modbus ASCII protocol in the modem settings only if it is recommended to use by the manufac-
turer of an external device.
2.10.3. Power Connector
The connector MicroFit 4 is used to supply power to the modem.

18
Fig. 2.6 Power connector
Table 2.2 Power connector pin assignments
Pin
Signal
Assignment
1
Not used
2
Not used
3
GND
Negative terminal of power supply voltage
4
+ Uin
Positive terminal of constant power supply voltage. Protected by a
fuse and overvoltage (when applying voltage to input of over 40V)
and reverse polarity protection circuit
2.10.4. Terminal Connector (2GPIO+1GPO)
Fig. 2.7 Terminal connector
Table 2.3 Terminal connector pin assignments
Pin (see Fig. 2.7)
Name
Assignment
1
GPIO3 (GPO)
Power general-purpose output
2
GPIO2/ADC
Configurable general-purpose output
3
GPIO1
Configurable general-purpose output
4
GND
Ground. Connected to the negative terminal of the power supply
1
4
3
2

19
2.11. The Modem Status Indication
To display the modem operation status, it is equipped with LED indication. The LEDs are placed above the
SIM card trays.
When you turn on the modem, both LEDs light up for 300 msec. In case of the RTC-timer failure, LEDs can
light up for 10 seconds while RTC is being initialized.
At the modem operation, the indication is performed via the LED placed above the tray with an active SIM
card (the SIM card operating at a given moment is called active, the second one –inactive). LED signal inter-
pretation is shown in Table 2.4.
Table 2.4 LED indication signals
Active SIM card
indicator
Inactive SIM card
indicator
Operating mode
300 msec on / 300 msec
off
Off
Module loading, SIM card verification, logging to network
150 msec on /
1500 msec off
Off
Establishing GPRS connection
Solid on
Off
GPRS connection is established, the modem is con-
nected
Off
Off
No power
Single simultaneous blinking (150 msec on / 150 msec
off)
Switching off and restart / switching on
Both LEDs are solid
Service mode
Both LEDs are blinking (150 msec on / 150 msec off)
SIM cards operation error (PIN code error or no SIM
cards in the trays)
2.11.1. Signal Strength Indicators
The ATM modem is equipped with the hard reset button1which is also designed to detect the signal strength
of the modem. This feature allows you to find an optimal location to mount the modem antenna on a site. Signal
strength is displayed in the log and indicated by the LED for each SIM card of the modem.
To determine the signal strength, press the button using a thin object and release it. The LEDs indicate the
signal strength within a minute, after that the modem returns to the previous operation mode. With GPRS or
CSD connection established, the connection is terminated by pressing the button, and after the end of signal
verification it is re-established. Signal detection is not supported in the service mode.
1The button is placed on the side of the modem with the RS232 connector (see Fig. 2.3). Early models are not equipped
with this button. The hard reset button function is described in section «Updating Firmware».

20
When pressing the button, both LEDs light up for 200 msec, after the pause of one second each LED starts
to blink in accordance with a signal strength of its SIM card.
Depending on the CSQ signal strength, the LED of each SIM card blinks certain times:
1 time –signal strength is below 9;
2 times –signal strength is from 9 to 15;
3 times –signal strength is from 16 to 19;
4 times –signal strength is from 20 to 24;
5 times –signal strength is over 24.
Each LED blinking lasts for 80 / 400 msec: 80 мs –LED is on, 400 msec –LED is off. The pause of 4
seconds is followed by LED blinking of certain number of times. After that the modem detects signal level and
the process is repeated –the LED blinks the number of times corresponding to the CSQ signal strength, then
follows a four-second pause –and so until a minute passes from the time the button has been pressed (see the
sample in Fig. 2.8).
Fig. 2.8 Signal strength indicators (a sample for the CSQ signal strength from 16 to 19)
2.12. Parameters and Attributes Used
Key attributes of the АТМ2-232 Modem:
1. Device model –Automatic Terminal-Modem ATM2-232.
2. Software version.
3. Hardware board version.
4. Device name –a unique device name containing 4 characters (digits and Latin letters). It is specified in
each SMS message1sent by the modem. The device name is used to distinguish SMS messages from
different modems. Case-insensitive: aaaa and AAAA –the same device name.
5. Default value –name.
1For example, the modem can send SMS messages in case of GPRS connection loss or on signals from external
pins.