Force reset to factory defaults LE910v2 while CFUN=7

3 thoughts on “Force reset to factory defaults LE910v2 while CFUN=7

  1. The LE910v2 modem (S/W ver) 20.00.402 connects to the data terminal only using USB and at commands are sent over USB-serial ACM interfaces.  While experimenting different methods of setting the modem to low-power standby, I set the CFUN mode to 7:

    [Taken from Telit_Modules_Software_User_Guide_2G3G4G_r20.pdf section 4.6]

    Type in CFUN=7, the module enters the CYCLIC SLEEP mode. It sets periodically the CTS control line to ON to enables the AT interface for a short time. The period, between two consecutive CTS OFF? ON transitions, extends from some sec to some tens of sec, its variability depends on the internal timing of the module. If characters are recognized on the AT interface, the module stays active for about 2 sec after the last character has been sent or received

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    Problem: after setting CFUN=7, the modem became unresponsive (does not enumerate itself as a USB device anymore), and there’s no more AT interface to send commands to.  

    Question:  Is there a way to recover from this?  Is there a H/W reset sequence that can be done to reset the NVM and return the modem to factory defaults?

    Thank you.

    1. Hi Louie,

      with CFUN 7 you enter in cyclic sleeop so you can send AT command ONLY if CTS is high.

      In this case send AT+CFUN=1 to return to normal mode.

      BTW: if USB cable is conencted you don’t enter in sleep mode and so you can use the USB to send AT command whenever you  need

      1. Hi Louie,

        with CFUN 7 you enter in cyclic sleeop so you can send AT command ONLY if CTS is high.

        In this case send AT+CFUN=1 to return to normal mode.

        BTW: if USB cable is conencted you don’t enter in sleep mode and so you can use the USB to send AT command whenever you  need

        Thank you for replying, Luca.

        The LE 910v2 modem module I’m using only has a USB connection (AT commands via USB-ACM) to the DTE (no UART).  After switching to AT+CFUN=7 by mistake, the DTE is unable to detect the modem via USB anymore (it does not enumerate anymore).  

        I will check if I can solder wires to the modem’s UART port so that I can try sending the AT+CFUN=1 command as soon as it wakes from cyclic sleep.

        Thanks.