TRB500 mobile (re)connection fails


I have been using 1 TRB500, without any significant issues, so I ordered 4 more. I’ve been testing them in the same network, and have problems ever since… It seems that only 1 of them is working properly (whichbis actuallybused as gateway) and the other devices are unreachable, (re)booting and or not making data connection. They seem to have an issue with the provider (KPN) and or the APN to gather a fixed IP adress (advancedinternet).

For the weekend I decided to take 1 at home and do some further testing. I needed to do a factory reset in order to get it working again…. I just found out that when disconnecting my laptop, whihtin a couple of minutes it looses connection and doesnt built up again (i’ve enabled sms notification of (dis)connection events)… 3 out of 3 tries this was the case.

Does the TRB500 need a specific job (as a gateway) in order to maintain its LTE connection?

Firmware 7.04.4



There have been issues reported with some firmware versions of the internal modem of the TRB500 and the KPN network. Could you post the internal modem firmware version (Status → System) of the device that is functioning properly, and of the device that is losing connection?
This will help me understand whether this is the same issue. For now, I’d recommend blacklisting the n28 5G band, and checking if the behavior repeats. Bands can be filtered by following this example: Band Lock - Teltonika Networks Wiki (simply do not include n28 into the allowed 5G band list).

Best regards,

During the weekend I took one of the TRB500’s at home and updates the firmware. I found out that when i disconnect the LAN port the device looses connection and has troubles establishing a connection again.

At work the 4 devices are connected through a switch but only one of them is actually used as a “gateway”, and this is the device with a stable connection, the other 3 are connecting and or booting al the time.

Furthermore of I rule out n28 than I definately have no 5G since this is the only band from KPN providentie 5G…

Could you clarify how you’ve configured this topology? What is the purpose for the rest of TRB500s?
Additionally, let’s continue on this thread, because information will definitely be missed if the same issue is discussed on multiple threads. Thank you.

Best regards,

I have several servers which require a fixed IP adress and I need at least 3 devices for the bandwitdh of the upload which is rather slow at the moment (20mbps): 1 camera server, 3 VNC servers 1 data server.
Camera server uses 1 TRB500 as gateway, 3 VNC servers occupy another TRB500, and the data server has the third TRB500 as gateway.

Hi Thanks for your help. Unfortunately im waiting already for 2 weeks for a reaction from my supplier. It seems they also have a supplier and are not directly in contact with Teltonkia

In the Netherlands we have 3 ISP suppliers with 5G, two of them use (only) band 28, so blacklisting this band means killing the 5G. I specifically bought the 4 devices for this purpose…

modem firmware of device losing connection (even with n28 blacklisted an latest router firmware): RG501QEUAAR12A05M4G_OCPU_BETA_20211020D_04.001.00.000

modem firmware of device working properly (with n28 blacklisted and latest router firmware): RG501QEUAAR12A05M4G_OCPU_BETA_20211020D_04.001.00.000


In order to resolve the issue that you are currently experiencing, additional provision of further confidential details is required. Since your supplier is not able to help you out, please contact us by filling out the Contact Us form here: Teltonika Networks - LTE Routers, Gateways & Modems for IoT
Our sales managers will help you get in direct contact with us. Thanks!

Best regards,

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