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Intermittend Modem failure or loosing Internet connection

Q: Some Data Loggers have suddenly stopped sending data.

This problem occurs when the Ydoc modem is losing Internet Connection.

When the error message “Modem timeout error” is shown during remote firmware upgrade (FTP or MQTT) there is a data gap of at least 10 seconds in the data stream.

A: Check these items to solve the problem:

  • Power problems**. The (Data Logger Internal) power to the modem has to be very stable. The modem is drawing a lot of current when active. Check is power (battery or external supply) is capable to deliver the the sufficient peak current. Check for low voltage, loose internal power cable or corrosion on power connectors on main board and power cable.
  • Main fuse problems**. It sounds odd, but a main fuse with internal resistance or corrosion on the main fuse holder can also generate power problems. Replace the main fuse, how to do, can be read in this FAQ.
  • Firmware version. Firmware version starting with V4.8 B7, has an Automatic Network deregister and register mechanism implemented to cope with sudden network subscribing issues. For firmware versions, check this page.
  • APN settings. Best is to configure the APN “Manually”, avoid use of the configuration settings, automatically provided from the network provider.
  • This could be a remote Server problem or a Network problem (Latencies or dropped connection).

**WARNING:  Due to Power problems, the modem flash-memory can get corrupted, resulting in an inoperable modem, and discontinued network /Internet connection.

C: For APN settings, check the Data Logger Manual, Chapter “Modem Settings”.

T: When a modem has gone defect (the modem’s flash memory has been corrupted) drop a support call. Sometimes, a re-flash can be done by the customer, sometimes a RMA is needed.

Example list of Data Logger error messages involved to this problem:

S;231023121011;ERR;NETWORK_REG;+CGREG: 2,2

S;231023120626;ERR;SERVER_LOGIN;+CME ERROR: context not opened


S;230822173031;ERR;SERVER_LOGIN;+CME ERROR: time-out in opening socket


S;230822090212;ERR;SERVER_LOGIN;+CME ERROR: connection failed



S;230420105503;ERR;FILE_OPEN ;+CME ERROR: can not setup socket


S;230420122035;ERR;CHANGE_DIR; +CME  ERROR: FTP unexpected reply


S;230420123542;ERR; SERVER_LOGIN; +CME ERROR: connection failed


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