Jetson Xavier AGX UART comunication

Hello All,
I’m a Jetson Xavier AgX board for my research. I need to send an SMS using sim800L module and jetson. here are the details of SIM800L GSM module (
the module uses UART protocol for communication. I powered the module and connected TX to pin 10 and RX to pin 8 in the Jetson I/O header. But still, i can not configure to send SMS via this module. I can find the serial port. Can someone help me with the correct procedure to do this task?
It will be a big help for me.

Just to make sure, did you use end A’s TX to end B’s RX? And end A’s RX to end B’s TX? This should work at 115200 8N1.

Thank you very much for the response. yes i did. all wired connections is fine. I think the problem is with the code. How do I identify the correct port number in Linux as “COM3” in windows

In Linux you will have a file in “/dev” for each serial port. A typical integrated port using older traditional drivers will have a numbered name prefixed with “/dev/ttyS#” (where “#” is a number). A typical name for the NVIDIA DMA-enabled driver will be of the format “/dev/ttyTHS#” ("THS" being “Tegra High Speed”). A typical USB serial UART will have a name of the format “/dev/ttyUSB#”.

An exception is that many third party installations will rename a “ttyTHS#” using the “udev” system. FTDI makes a lot of serial UARTs used by third parties, and to differentiate, the “driver” for such devices may make a udev rule to alter the name to their custom name even if the driver is still FTDI. There are also other common drivers which always change naming convention.

On the side of the UART which is USB you can monitor the logs with “dmesg --follow”, and then insert the USB connector. The log will show the device is connected, and if a UART driver takes ownership of the hardware, then the log should also show the name of the “/dev/ttySOMETHING”.

The side of the communications which is purely UART, without USB, won’t have any particular easy method of knowing the port name without either reading documentation on the product or trial and error.

If you look at all tty devices, many of them will be of name format “/dev/tty#”, and none of those will be serial UARTs (though they might be serial software). Among those devices you can usually look at the “group” of the file permissions and anything which is group “tty” will be either a regular console or a serial console; any device which is group “dialout” will likely be free for use. Thus look at the command “ls -l /dev/ttyS* /dev/ttyTHS*” on a Jetson and you can probably limit your possibilities to the “dialout” devices. This is true also for USB serial UARTs, but I am limiting this suggestion to finding the integrated serial UARTs of a Jetson which are not USB.

The Xavier does have some other names related to the micro-B USB connector’s serial console.

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