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Jazz RS232 serial communication with Teltonika RUT906 not working

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I have a project where data was read from PLC using a Siemens TC65 modem and MJ20-PRG module and now the intention is to replace the TC65 modem with Teltonika's RUT906 and read data via RS232 serial communication. 

The problem is that Teltonika cannot connect via serial communication to Jazz. Tested using the Modbus Poll program.

The serial port settings are defined in the program and power supply added to pins 1 and 6.

Are there any settings that can be used to specify that the MJ20-PRG is used for RS232 serial communication?


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  • MVP 2023
13 hours ago, NiHa said:

Are there any settings that can be used to specify that the MJ20-PRG is used for RS232 serial communication?

Unfortunately, I did not find a complete manual for this device on the quick link, but for practical advice, I would recommend checking the transmission TX and reception RX conductors between the adapter and the router.

It very often happens that when trying to connect with the wrong cable, a direct connection is used instead of a crossed one or vice versa (TX-RX, RX-TX connection).

It should also be noted that connecting an additional power supply with a voltage higher than that recommended by the manufacturer will damage the adapter MJ20-PRG.

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There is working Unitronics solution with Unitronics Router UCR-ST-B8.

Jazz PLC connecting to Router's RS232 port.

After additional Router configuration Jazz PLC may be used as an external MODBUS RTU device in UniCloud.

Open link https://www.unitronicsplc.com/support-technical-library/

Scroll to Accessories->Routers




Unitronics use proprietary Firmware to support UniCloud.

UniCloud link:



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