5G M.2 TO RJ45-KIT with RM520N - how to send AT commands?

[Galvanize47]

I didn't think I was this clueless but I'm beaten and admit defeat.
I installed the RM520N-GL into the carrier, connected the antennas and stuck my Mobley SIM in. I have a red power led and green 'net' light
Now how do I connect my MacBook to the M.2 to RJ45 carriers USB debug port to get a connection so I can enter AT commands and turn on the Ethernet port?
Do I need to use a Windows machine? Do I need a some kind of special serial > USB-C cable?
I tried connecting my Macs USB-C port directly to the M.2 to RJ45 USB-C debug port but nothing shows up in the system information and I'm not able to open a connection using decisive tactics' 'Serial' program which is my usual go to solution.
I've tried a few different USB-C cables with no joy. I'm clearing missing something real obvious here.

EDIT: It was a dead on arrival board, seller refunded me after providing a video of the modem not being recognised on USB or ethernet connection.

[Didneywhorl]

Nothing shows up? Not even an errored device? Generally IF the usb is enabled something should pop up on the usb bus.

Have you tried via Windows?

Does anything load when you enter https://192.168.225.1

[Galvanize47]

Nothing shows, errored or otherwise on the USB connection.
Nothing shows up on the RJ45 port either, no link or activity lights, or traffic, I assumed it was disabled until I did some AT command configuration.
I've been an exclusive Mac home for a while now but I pulled out an old Lenovo laptop to test with. I dont see anything appear in detected USB and don't see any COM ports available in QCOM 1.6.
This lack of anything working anywhere is what led me to believe I needed some magic cable.

The modem appears to be online as I see a green LED and the data usage on my AT&T account slowly increasing during the day.

[Didneywhorl]

Sounds like a bad board maybe, but really hard to tell. One or the other should work, especially the USB.

Which specific board do you have?

[Galvanize47]

https://www.aliexpress.us/item/3256804672394777.html

[Didneywhorl]

Did you buy it with the modem already installed, or separately?

[Galvanize47]

Separately.
EDIT: Tried reseating it but no luck, dead on no output on either port.

[Didneywhorl]

Happen to have another modem to test in it?

[Galvanize47]

I did just try an EM7565 and still no USB or ethernet activity.
Also tried a different PSU just in case.
I'm pretty sure this is just DOA at this stage and will try and process a return with Aliexpress seller.

[FiveJeezy]

I don't think it's a bad board. If you put your own modem in the enclosure, most likely it has never been configured to send data through the ethernet port (if that is your end goal, you'll definitely need to send AT commands). But Didneywhorl is correct, it should at least work through the USB port. My guess is that the modem is in QMI or MBIM mode, which Macs can't use. Macs can natively support ECM mode (however, even in ECM mode, I haven't found a way to send AT commands through Mac). My question is, when you tried it on a PC, did you install the USB drivers first?

[Didneywhorl]

I don't think it's a bad board. If you put your own modem in the enclosure, most likely it has never been configured to send data through the ethernet port (if that is your end goal, you'll definitely need to send AT commands). But Didneywhorl is correct, it should at least work through the USB port. My guess is that the modem is in QMI or MBIM mode, which Macs can't use. Macs can natively support ECM mode (however, even in ECM mode, I haven't found a way to send AT commands through Mac). My question is, when you tried it on a PC, did you install the USB drivers first?

...I've been an exclusive Mac home for a while now but I pulled out an old Lenovo laptop to test with. I dont see anything appear in detected USB and don't see any COM ports available in QCOM 1.6.
...

Yeah, they tried it on Windows, see above quote; it was buried in the middle of his response.
It should at least show up in the device manager as an unknown device. Mac is similar to Linux (Unix fork based?), if I recall, with these modems in that it generally will recognize the USB device as something. I could be wrong of course as I am not really a mac user ... like at all. Linux, obviously not the same thing as mac, just seems to see it. Already has drivers in the kernels these days.

I completely agree, unless they shipped it with the modem inside, it wont be able to use the RJ45, but the USB on these boards are active for data and AT commands. I think it's a dud. I've got a pile of duds, it happens. Sucks when its your only one though.

[Galvanize47]

Thanks folks for your input here. Windows didn't prompt for any device drivers when connected hence my conclusion the USB port was dead. Without being able to communicate to the modem and enter T commands I can't activate the RJ45 port. I've opened a request with the seller for a return / replacement and am waiting for them to get back to me. I've ordered another carrier board from a different vendor so hopefully the modem is fine and I can just write off the 5g to RG45 carrier cost.

[Galvanize47]

The good news is the Mcuzone 5G to RJ45 board worked out of the box, modem shows up on my Mac immediately. It's a dead board from China but at least now I have a functioning board to create a video as requested to get a refund or replacement with.