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GX LTE 4G manual

5. Troubleshooting

In this section:

5.1. Troubleshooting guide

There are many reasons for a modem internet connection not working. Carefully go through each step of this troubleshooting guide. Make sure to start at the first step. When asking for help, make sure to mention each step taken and the result.






Check that the blue LED is either lit continuously or blinking.


USB connection

The modem must be connected to USB and visible in the Settings → GSM modem menu.


SIM card status

Check the SIM Status in the menu; it must show “Ready”. It will show “SIM not inserted”, “PIN required”, or “PUK required”, and more related errors when there is a problem. Please refer to the SIM status list for details.


Signal strength

One bar is the minimum for VRM logging; 2 or 3 bars are necessary for a working remote console. An outdoor antenna typically increases the received signal by 15 to 25 dB.


Carrier registration

Check that the name of a Cellular provider is visible in the “Carrier” field. If it is not, check signal strength and otherwise contact your SIM card provider and/or insert the SIM card into a phone to double-check its operation and subscription status.


Internet connection

Verify that the Internet shows “Online”. Reasons for the system to not go “Online” whilst properly registered on the Network are:

1) APN not configured, contact the network operator for details.

2) The network is a different one than the home network (ie. roaming), and the setting to permit Roaming is disabled.

3) Signal strength is strong enough to register on the network but not to open the data connection to the internet.


Connection to VRM portal

Verify that the VRM Portal menu shows a recent last connection time. See Settings → VRM Portal. For more details, see the VRM Connection troubleshooting chapter of the GX Manual.


Note that Ethernet and WiFi connections have priority over the cellular connection. Even when the available Ethernet or WiFi connection does not have a good connection to the internet, there is no automatic detection in place which in such case switches over to the GX GSM. In more technical language: when the cellular data connection is active, it is configured with a high routing metric. This way, the Linux kernel prioritises Ethernet or Wifi when these are available.

5.2. What to do if the GX LTE 4G is not staying connected?

Enable the “Reboot device when no contact” configuration setting in the VRM menu of the GX device. That will reboot the GX (and with it the GX GSM) automatically if the internet connection is not available. See also the configuration chapter for more details.