Can't connect PC to Dragino LSN50

Hi folks, I recently bought Dragino LSN50, EU868. Node is joining the network without problems. But, if I try to connect a node with my PC using serial cable and LogiLink USB-to-Serial converter, all I get to PuTTY terminal is garbage. Node doesn’t react to ATZ command. I checked several times for pin definition, but no luck. Is anyone faced (or still facing) that kind of issue?
Any suggestions?
Thank you in advance.

Welcome at this site

Did you follwing the info from Dragino Wiki http://wiki.dragino.com/index.php?title=Lora_Sensor_Node-LSN50#Getting_Start
special at topic 2.2 " Use the AT Command"
regards

Johan

Hi Johan, Thank You and sorry for the late answer. Yes, I checked several times, but no luck at all.
I uploaded a picture (JP2 is off).
Dragino

Any other idea?
Thank You in advance.

BR,
Aleksa

Ask Dragino ?

Yes, that is my next step :blush: Thank You.

Best regards,
Aleksa

Pictures that result from web searching for that cable seem to show something ending in a 9-pin D-SUB connector (technically a “DE-9”). Such cables almost invariably use RS232 signaling levels.

In contrast, your node requires signals of approximately 3.3 volt level which are inverted in sense from RS232.

Not only are RS232 signals “upside down” with respect to what the node needs, their excessive voltage may well have already caused permanent damage to the MCU’s receive pin

If you are lucky, getting a “logic level USB UART” as typically used for Arduino projects may work. If you are unlucky, the node or at least its MCU will have to be replaced.

To verify if this is the issue, please show the end of the cable and how you have wired it to the module, not just bare wires going into the module’s screw terminals.

Hello, cslorabox,
thank You for the answer. And, I must say that Your answer is probably correct, but we must investigate more.
This is a picture of LogiLink AU0002E, together with extension cable RS232 straight-through (cable have female and male connector):
001_Pic
Technical details about USB2Serial convertor are on this link:
https://www.buerklin.com/en/Products/Test-&-Measurement/Computer-Accessories/Adapter-and-Converter/Adapter-Converters-Docking-Stations/USB-to-RS-232-adapter-USB-2-0-RS-232-true/p/12M361
On the other end of an extension cable, You can see male connector (following picture - both rounded by the red ellipse)
002_Pic
And, finally, the next picture shows pins that are connected to Dragino LSN50:
003_Pic
The red circle is GND (according to RS232 pinout diagram), Yellow circle is RXD, and the Green circle is TXD. They are connected to GND on Dragino (Red marked pin is connected to GND on Dragino), RXD (Yellow marked pin) is connected to PA2 on Dragino and TXD (Green marked pin) is connected to PA3 on Dragino, as the Dragino LSN50 Wiki suggested (http://wiki.dragino.com/index.php?title=Lora_Sensor_Node-LSN50#Use_the_AT_Command).

Can You suggest what TTL converter we should try, please?

Best regards,
Aleksa

Alas, those are clearly RS232 level devices. At best they will not work, but its quite likely they have already destroyed the involved part of the chip on your node board.

There are many different cables sold for Arduino, pi, etc type projects - they should give the signal voltage levels in the description but visually they tend to terminate in individual wires or a header type connector, not a D connector. I mostly tend to buy the CP2102 / CP2104 ones that are small boards with a male header where you connect whatever you like but it’s a matter of personal preference, mostly because that chip doesn’t seem popular enough for fake versions to be common (PL2303’s are widely faked, and in more recent years FT232’s as well)

Many would suggest avoiding those with CH34x chips as driver support has been iffy.

Merry Christmas to all who celebrate today!

Thank You cslorabox. We are trying to purchase proper board. I’ll inform about progress.
Thank You for answer.
Good lack to all.
Best regards,
Aleksa