TRB255 device offline but Telco active with no data


I have several TRB255 devices connected to a Cat M1 network. The device is registered with the Teltonika RMS. The device runs okay for weeks, then goes offline. The device is displayed as offline in the RMS, and is unresponsive to SMS based status/reboot commands. A hard onsite reboot is required.

However, the Telco provides a user portal to manage SIM connections, the device displays as online. The device has an IP. The data transfer is zero.

This problem has happened 5 times this year. The SIM has been swapped out, a replacement TRB255 has been swapped in. The Telco investigation reports the device is ‘idle’, and their network has no problems.

  • The TRB255 firmware is: TRB2 R 00.07.04
  • The SIM network is set to manual and uses the Telco APN settings
  • The majority of the default open firewall ports and services are closed
  • The TRB255 is the only Teltonika product that supports our needs - Cat M1, RS232 input, LAN, and power input, otherwise we would look to an alternative product.

All previous forum posts are not accessible. Does anyone have any ideas on how to resolve this issue?



Firstly, updating to the latest firmware version would be a good initial step. There are always some improvements to the device operation and performance, though it’s worth noting that this might not necessarily resolve your specific issue.

Is this a problem occurring across multiple devices or is it isolated to just one?

When the issue arises, can you access the device’s WebUI from the local network? If so, I recommend downloading a troubleshoot file from System → Administration → Troubleshoot during the next occurrence. The system logs contained in this file may provide clues as to what’s causing the issue.

I would suggest setting up a ping-reboot function which is beneficial in cases like this. This way, the device should reboot itself whenever it loses internet connectivity. Ping-reboot information is available here.

Kind Regards,

Hi AndzejJ,

Thanks for the response and tip. I will look into the ping reboot on a local separate device, however it shouldn’t require such an action. My problem is the offline device is 1500km away in a remote location. The 4hr based LTE telco provider reports the device is active and registered with an IP, and reports receiving SMS requests i make to reboot or report the status. Although the device is not sending data and it is reported as offline in RMS.

The issue has happened on two different TRB255 devices. The first unit was running a previous stable firmware when the problem first happened a few weeks after deployment. The firmware was updated, but the problem remained. The SIM was replaced, but the issue remained.
A second TRB255 device was swapped in, using the same upgraded firmware as the first device. The replacement SIM was used in the second device.

Troubleshooting logs were downloaded from device one and two with both firmware. I have looked at the Troubleshooting logs, however i am not knowledgable enough to be able to identify the issue cause.

The config is simple: serial data from the RS232 port is pushed to AWS, and a LAN device. Other than running the NTP server, connection to the RMS, and with closed ports and most services off, it a simple config.

I am not sure how to resolve the TRB255 issue. I am hoping someone has experienced this before and resolved the issue. Otherwise i am likely to ditch the TRB255s. The ping reboot sounds great as a stop gap but the device shouldn’t require this.

Any other ideas welcomed!!