Trying to understand and get Nx_TCP_Echo_Client to work on B-L462E-CELL1

JFlowers · ‎2025-05-26

OK, I have a STM32L462RE Discovery Kit (apparently a.k.a. B-L462E-CELL1).

I am trying to get its sole Demonstration application to work (STM32CubeExpansion_CELLULAR_V7.1.0\Projects\B-L462E-CELL1\Demonstrations\Nx_TCP_Echo_Client), but I can’t even tell how it is supposed to work.

I see “TCP_Echo_Client” in its name, so I assume if I have a simple TCP echo server running on my workstation that if I do the appropriate port forwarding through my router along with the appropriate Windows Firewall settings, then I should see the B-L462E-CELL1 connect to my local TCP Echo Server.

Is that correct?

Further, I assume that in this file:

STM32CubeExpansion_CELLULAR_V7.1.0\Projects\B-L462E-CELL1\Demonstrations\Nx_TCP_Echo_Client\NetXDuo\App\tcp_echo_client.c

I should change TCP_SERVER_PORT from 7 to whatever TCP port my local TCP Echo server is running on, AND I should change the TCP_SERVER_ADDRESS IP_ADDRESS(52,215,34,155) in that same file from 52,215,34,155 (which implies 52.215.34.155) to whatever my public facing router’s WAN address is.

Is that correct?

If all of that is right and my SIM card is working right, which I think it is - I’m see messages like this on bootup: “Network is up with IP 10.228.182.49” on TeraTerm - then I should see “10.228.182.49” (or whatever IP address is given my B-L462E-CELL1 on bootup) connect to my local TCP echo server.

Is that correct?

Further, I assume that on my TeraTerm console connected to the B-L462E-CELL1, that I will see some sort of confirmation that my local TCP Echo server replied back to the B-L462E-CELL1 with the exact same message that the B-L462E-CELL1 originally sent to it (to my local TCP echo server).

Is that correct?

Where do I change the message that the B-L462E-CELL1 sends to my local TCP echo server?

Help, please.

STackPointer64 · ‎2025-05-27

Hello @JFlowers ,

I see “TCP_Echo_Client” in its name, so I assume if I have a simple TCP echo server running on my workstation that if I do the appropriate port forwarding through my router along with the appropriate Windows Firewall settings, then I should see the B-L462E-CELL1 connect to my local TCP Echo Server.

If your router drops ICMP packets by default, then yes you need to allow them in your firewall settings. To verify this, if you possess two devices connected to the same network, try to ping one device from the other using the command below and see if you get a response or not. If you do, no port-forward or firewall configuration are needed.

ping IP_ADDRESS

In case you wish to run this application in a Wide Area Network, then you are correct port forward and firewall configuration are needed.

Further, I assume that in this file:

STM32CubeExpansion_CELLULAR_V7.1.0\Projects\B-L462E-CELL1\Demonstrations\Nx_TCP_Echo_Client\NetXDuo\App\tcp_echo_client.c

I should change TCP_SERVER_PORT from 7 to whatever TCP port my local TCP Echo server is running on, AND I should change the TCP_SERVER_ADDRESS IP_ADDRESS (52,215,34,155) in that same file from 52,215,34,155 (which implies 52.215.34.155) to whatever my public facing router’s WAN address is.

Correct.

If all of that is right and my SIM card is working right, which I think it is - I’m see messages like this on bootup: “Network is up with IP 10.228.182.49” on TeraTerm - then I should see “10.228.182.49” (or whatever IP address is given my B-L462E-CELL1 on bootup) connect to my local TCP echo server.

Correct.

Further, I assume that on my TeraTerm console connected to the B-L462E-CELL1, that I will see some sort of confirmation that my local TCP Echo server replied back to the B-L462E-CELL1 with the exact same message that the B-L462E-CELL1 originally sent to it (to my local TCP echo server).

Is that correct?

Where do I change the message that the B-L462E-CELL1 sends to my local TCP echo server?

I suggest you refer to UM2426 which is dedicated to explaining in detail the the XCube-Cellular package specifically "How to customize the software?" section and let me if it did help you.

Best regards,