3G/GPRS connection goes down and does not recover again

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Error Definition[edit | edit source]

  • After a duration of successful communication, 3G/GPRS connection goes down and does not recover again.

Components To Be Checked[edit | edit source]

  • Make sure your sim-card's data quota is still enough to connect to the internet. Contact your operator to check this.
  • Check if PPP is enabled in the firmware or not. You can use AT+INCLUDE=? and see if "PPP=1" exists ( on Mikroterminal). If PPP is disabled check the CSQ level(AT+CSQ=?) and simcard state (AT+SIM=?)

Possible Solutions[edit | edit source]

  • Sometimes GSM operators resets the line. If you are using a PPP(Point to Point) enabled firmware you need to set the "LwipTmo" value other that zero to recover the connection back again. "LwipTmo" can be set through a special register on the device via MODBUS. Modbus register address "15" keeps that value. A value like "120" will be fine for most of the applications. After a "120 seconds" timeout the device will clear the line and reset the connection.