Question

Hello!

We have a TRB245 placed out in the field. It has been working great for a while as a modbus serial gateway, but it recently stopped accepting connections.

After further investigation the menu item for "modbus serial" is missing in the web interface. Trying to start the modbus_serial_master from command line throws the following error:

root@Teltonika-TRB245:~# modbus_serial_master  --rs485 19200
Failed to open serial device

Advanced mode is selected in the GUI.

Help?

Answer 1

Hello,

From the screenshot you have provided, it can be seen that no RS232 or RS485 section is displayed. I believe this is what you are missing. In this case you can try a couple of things:

• Reboot the device;
• Upload firmware, following the bootloader procedure, which is described in this page: https://wiki.teltonika-networks.com/view/TRB245_Device_Recovery_Options#Bootloader_menu.
• Connect to the device via SSH, enter command ls /dev and post the output screenshot here.  

  If none of this helps, it is highly likely that the issue is related to a hardware failure and you should return the device. 

Best regards,

Žygimantas

Comments

Thanks for the suggestions.

Reboot is not helping unfortunately. I only have access to the TRB245 over ZeroTier, so using the Bootloader menu externally seems to be a no-go. I would have to go and collect the device in order to try that.

Here's a screenshot of ls /dev

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Hello,

Apparently, RS232 and RS485 instances are missing, which is another indicator of hardware failure.

Best regards,

Žygimantas

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So I went a purchased another device, and the same thing has happened with that one. RS484/RS232 menu is missing in the menu after a while of working perfectly, any idea why this is happening?

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Could you provide any description, schematic or photo of your setup?