Equisys technical notes

Technical guidance, explanations and fixes for our products

PRB: Unable to send SMS alerts with GSM modem



ID: ZTN1262

This Zetalink technical note applies to:

  • Zetafax version or later
  • Zetalink Version 3.0


Zetalink reports the SMS alert/summaries are sent successfully, however:

  • SMS alerts never arrive on the user's mobile phone.
  • SMS alerts are queued on the Zetafax communications server and the SMS device is reporting errors sending in the server log.


The GSM modem is failing to send SMS alerts. Possible causes are the Network coverage, signal strength, a busy network or the modem is incorrectly configured. Some help is provided below on what to check.


Stop the Zetafax communications server.

Open a connection to the Wavecom GSM Modem as follows.

  1. Run 'HyperTerminal' - Start | Programs | Accessories | Communications | HyperTerminal.
  2. When prompted to name the connection type in 'Test' and click OK.
  3. You will then be asked which modem to connect with, choose 'COMn', where 'n' is the COM port number used by your GSM modem. Then click 'OK'.

  1. On the properties page for 'COMn' click 'OK'; do not change the Port settings.
  2. You should now be able to communicate with the device directly using standard AT commands.
  3. Check the LED is flashing on the GSM Modem (the LED is only available on the modem).
  4. Check that the SIM card synchronised on the network with the command 'AT+CREG?' If it did the answer should be '+CREG:x,1' and if it didn't synchronise you should get the response '+CREG:x,5' .
  5. Check that the SIM card is properly inserted into the device and that you have disabled the PIN code request.
  6. You can check the signal level with the command 'AT+CSQ'.  It should respond '+CSQ:' , with the 'RXLev' preferably > 10. If the RXLev is lower than 10 this could mean that it has a weak signal level, therefore check your antenna (connection with band) and network coverage.
  7. To check the status of the " visible" networks use the command 'AT+COPS?'
  8. Check the status of the locks (SIM lock, network lock etc) with the 'AT+CLCK?' command.

If the device is synchronised on the network (i.e. successfully negotiated reception with the network provider) then check the SIM in an alternative mobile phone/device. Try to make a call and send an SMS message. If a Pre-pay SIM is used check for Airtime credit.

Check the SMS message service number is correct in the device configuration on the Zetafax communication server.

The Implementation guide will provide the defaults for some of the common networks at the time of print. The service centre number can be checked buy putting the SIM into a phone and verifying the messaging options; you can consult the user manual for your phone for further details.

Commands to send a test SMS message from the modem using HyperTerminal.

  • AT+CMGF=1                                                                                                        (this puts the modem in text mode)
  • AT+CSCA=" +447973100973"                                                           (data centre number, unique to GSM provider)
  • AT+CMGS=" +447968493636"                                                         (mobile number to send to)
  • Enter the text message that you wish to send, up to 160 characters.
  • CTRL+Z                                                                                                                      (send message)


This has been identified by Equisys as functioning as designed with the software versions given above.

Last updated: 23 May 2003 (JG/LD)

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