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Cellular modules for machine-to-machine (M2M) communication including GSM/GPRS, CDMA and 3G. GPS, Zigbee, short range RF

Telit is a wireless technology company that designs, develops, manufactures and markets GSM, GPRS, UMTS, HSDPA, CDMA and short range RF (including WiFi and ZigBee) communication modules for m2m applications. The company’s technology and products enable other electronic devices and equipment manufacturers to utilize GSM and GPRS cellular infrastructure to relay and accept information without human intervention. m2m applications therefore enable machines, devices and vehicles to communicate via wireless networks.

Telit’s m2m solutions utilize a proprietary protocol stack, the software for the cellular engine, that facilitates communication between industry vertical applications and a wireless network.


Frequently Asked Questions


For xE910 modules, what are the minimum RS232 (UART) connections that I need to have?

The absolute minimum with no flow control is RXD and TXD.

For hardware flow control, the minimum lines are TXD, RXD, CTS and RTS

If you want to have flexibility, adding DTR and RING are helpful. DTR can be used to toggle the module from data online mode to command mode as well as control the power save mode of the module. RING can be used to know when incoming events occur without having to monitor explicitly for URCs, though monitoring URCs and also RING is the best combination.

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How do I order parts with older software versions on them?

Telit will manufacture all current and past Software versions as long as it is specified when placing an order. So if you did your development with software version 12.0.003 for instance, and you wish to stay with this version, Telit will continue to manufacture these particular versions with no problem even after newer ones become available.


Telit issues individual part numbers (SKU’s) that identify the Software revisions of their product. Therefore, you can specifically order this or any other version any at given time, as long as you reference the complete Telit part number when you place your order. The complete Telit part number (SKU) is located on the quote provided by Symmetry. Please contact us is if you are unsure which part number you should use for an order.



I would strongly advise you to have a method of updating the module software in the field. This will allow your products to take advantage of the latest The Telit modules offer various methods of updating their software, both over the air and through their hardware ports. Please see the FAQs on software updates for an overview of how this can be done.

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Where do I get the latest software for my Telit module?

Telit continually updates the software for their cellular modules to incorporate bug fixes as well as new functionality.


The latest software is available free of charge. Just provide us with your module’s part number and current software version and if there’s a newer version available we will email it to you.

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Where do I find documentation for my Telit module?

Telit provides most of the documentation needed by the designer on their website. There is no account or password required, just go to and look for the product page of the specific module that you are using. Under the “More Info” heading, click on “Downloads”. This will take you to a list of the documents in pdf format.

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What sleep/low power modes are available on the Telit modules?

There are several sleep/low power modes available, depending on the specific module that you are using. An important point to know is that the module cannot go into sleep mode with the USB connection still active. This is because the VUSB voltage may back-power the device, preventing it from going to sleep. So for an implementation that uses USB, it is recommended to still have access to some of the UART lines that can control sleep mode. If not all the lines, then at least RTS or DTR, which can be used to enter/exit power saving mode.


For a detailed explanation of the power saving features of your module, please see the Telit Software User Guide for your specific module. This can be found on the product page of your module, at

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There are so many Telit documents, how do I know if a certain document is applicable to my module?

Each Telit document has an Applicability Table on page 2 which states exactly which modules and software versions the document is applicable to.

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How do I configure the STAT LED pin?

The STAT LED can be useful in early debugging, since it quickly indicates the state of the module. Typically the STAT LED is used to indicate the connection status as shown below.


LED Device Status
Permanently off Device off
Fast blinking (period 1s, Ton 0,5s) Net search / Not registered / turning off
Slow blinking (period 3s, Ton 0,3s) Registered: full service
Permanently on A call is active


For many Telit modules, the STAT LED pin is not configured for this functionality by default. To configure it, issue the following AT commands:

AT#GPIO=1,0,2            // Set the GPIO to Alternate Function

AT#SLED=2                  // Enable STAT LED

AT#SLEDSAV                // Saves the setting

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STAT LED stays on during low power mode

Question detail:

I am working on some firmware for putting the Telit CE-910 DUAL into low power mode.  The issue is we have an LED connected to GPIO_01 of the chip.  Normally, my FW sets this up to indicate network status.


I put the CE-910 into low power mode by doing the following:


Issuing AT+CFUN=5

Raising /DTR signal to a high voltage


The power level drops, as expected, and AT communication does not work when the chip is in this mode, as expected.  My issue is the GPIO_01 circuit turns the LED ON continuously.  I tried using the AT#GPIO=1,1,1 command, and this DOES turn the LED OFF when the modem is in normal mode (/DTR signal is low).  But as soon as I raise the /DTR signal the GPIO_01 driven LED goes on and stays on.


The LED is drawing about 30% of the system power consumption when the modem is in low power mode.  I would like to make it stay OFF in low power mode (or maybe just occasionally blink).



The easiest way to avoid this issue is to set the GPIO to an input before you turn on power saving. For the xE910 modules, the STAT LED is located on GPIO 1, so we can set this to an input by issuing the command:




This command should be issued BEFORE putting the module into low power mode. After exiting low power mode, you can send the following command to reactivate the status LED:



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What is the best type of battery to use with my xE910 module?

Question detail:

In the xE910 HW specification, it is said that the maximum voltage allowed is 4.2V (Normal Operating voltage range). Some of the latest Li-on batteries, when fully charged will rise to 4.5V (Extended Operating voltage range). Will there be a problem?




Note: This explanation is for the case where the battery is directly connected to the cellular module, with no power conditioning circuitry. If you are using a power conditioning circuit you can use whichever battery you would like, as long as your circuit is able to provide the needed voltage and max current specs required by the module.


The module is best supplied by a 3.7V Li-Ion battery type when directly connected to the module since the 4.2V operating voltage can be met with this battery type.

The three cell Ni/Cd or Ni/MH 3.6V nominal battery types or 4V Pb(Lead) types must not be used since when directly connecting to the module the 4.2V range could be exceeded when the module is operating.

The module has an extended voltage tolerance of 4.5V however the module is not intended to operate at this voltage, only survive it.

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How do I provision my CDMA module?

CDMA modules have to be provisioned before they can be connected to the network for the first time. Once the module is provisioned for your network, you will never have to repeat this procedure.


Different carriers have different methods of provisioning. To get the latest steps for provisioning your module, open the Software User’s Guide for your specific module and look for the Provisioning section. The Software User’s Guide can be found on your module’s product page from

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I have a Verizon module but I would like to use Sprint, can I just update to the Sprint Software?

Question detail:

This question is applicable to any change of carrier on a CDMA module. The GSM modules are set up by the SIM card and do not have this limitation.



Telit’s CDMA modules do NOT support cross-carrier flashing.  There are more items that separate the carriers than a software version. Please contact us if you have a part for the wrong carrier and we will be happy to assist you in getting the correct parts.

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How can I do In Field software updates of my cellular modules?

In Field updates are a crucial part of any cellular design. Telit continually updates the software for their cellular modules to incorporate bug fixes as well as new functionality.

Note: The words Software and Firmware are used interchangeably in this context.



There are various ways in which you can update the software on a Telit cellular module. The simplest methods use a cable to connect the module to a PC and upload it that way. The more advanced methods allow you to update the module over the air, using the module’s cellular connectivity to download the new software.


Using a cable connection:

Most of the Telit cellular modules can use either a USB or UART connection to update the software. You will need both the programmer software as well as the new software for your module to do the update. These are available free of charge, just contact Symmetry/Semiconductorstore and we will be happy to assist you with these. The reason why Telit doesn’t make this software available freely on their website, is to protect their IP as well as to prevent customers from accidentally loading a wrong software version onto a module, which could damage the module.


Over The Air:

This is often the most cost effective way to update the software on a Telit cellular module, since it doesn’t require a technician to make a site visit. Telit offers a Premium FOTA Management service for modules on their m2mAir network. Please check the Telit website to see if your module qualifies for this service.


Some customers choose to implement over the air updates themselves. To do this you will need to sign an NDA with Telit to get the definition of their Stream protocol that is used to upload new software/firmware to the module. You can then design your system to download the new module software/firmware and perform an update of the module through the UART or USB port.

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What Operating Systems do Telit have drivers for?

It’s not necessary for you to use a host with a high level operating system. The Telit modules have an internal TCP/IP stack so that the host can be a simple micro that communicates with the Telit module via AT commands over a UART.


For more advanced hosts that can support a high-level operating system, the Telit modules can be used as a point-to-point connection with the host running their own TCP/IP stack. To support this configuration Telit offers drivers for Windows, Linux and Android operating systems. Just contact Symmetry/Semiconductorstore and we will send you the correct driver for your module.

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My application requires both Cellular and GPS features, should I use a cellular module with built in GPS, or separate cellular and GPS modules?

Two important aspects to consider are physical size and power consumption. A cellular module with built-in GPS will offer the smallest solution. If your system requires extremely low power consumption and has long periods where only GPS/GNSS operation is required then using separate Cellular and GPS/GNSS modules will offer lower power consumption. This is because the combined Cellular + GPS/GNSS modules use the same silicon chipset for both functions, so in order to use the GPS functionality they have to power up the cellular portion too, resulting in greater power consumption compared to using a GPS/GNSS module alone.


Telit offers a comprehensive line of GPS and GNSS modules that can be used for precise navigation and timing. Please contact Symmetry/Semiconductorstore for help in selecting a GPS/GNSS module.

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Where do I get the certification documents for a Telit module on a certain carrier?

Telit tries to certify their modules with all the major carriers. As a start you can check you module’s datasheet to see if it is recommended for use in the country that you intend to deploy it in. To get the latest certification for your carrier just contact Symmetry/Semiconductorstore.

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Can someone check my cellular schematic and board designs?

Telit offers a free design review service that reviews both schematics and board layouts. Symmetry/Semiconductorstore recommends this service to all customers, as it eliminates many common problems that can keep your cellular design from passing certification. Telit will keep your proprietary design info confidential and generate a report on your design to highlight possible problem areas.

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Can I run my whole application on the module’s internal Python engine?

Many of the Telit modules contain a Python interpreter. This is meant to complement the features of the module and give it greater flexibility in implementation. It is not meant to replace the traditional host processor that should both run the application and manage the cellular module. The interpreted nature of the Python script makes it much slower than a complied program running on a dedicated micro, because the Python task has to be shared with the cellular tasks on the module’s processor.


With that said if the application is simple and doesn’t require rapid real-time execution it may be possible to implement the whole application on Python. To check if this is possible we recommend that customers first implement the application on a Telit evaluation board.

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Do I need hardware flow control or can I just use RX and TX without the flow control signals?

The purpose of hardware flow control is to make sure that you don’t lose any data. We always recommend using HW flow control if you are sending or receiving data. If you are just sending AT commands to the module you are fine without hardware flow control.

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Can I concurrently run Socket Listen, Socket Dial and TCPATRUN sessions on the HE910/UE910 module?

Yes, the socket dial and listen commands can run on the same AT instance, but different sockets.  One can be used for #SD, the other can be used for #SL. The TCPATRUN must have an instance all of its own. That can be configured using the AT#TCPATRUNCFG command.


For example using PORTCFG =1:

Instance AT0 (USIF0)

  • Socket Dial (Socket 1)
  • Socket Listen (Socket 2)

Instance AT2

  • TCPATRUN (Configurable through TCPATRUNCFG command)


Please refer to the “Telit_HE910_UE910_Family_Ports_Arrangements” document for an in depth description of the different port configurations available on the HE910/UE910.


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