I have the modem installed in an M.2 to USB 3.0 housing. When I connect this to a machine, I see the two (2) expected TTYs (1 x NMEA and 1 x AT Command) get created. I can access the TTY for AT commands with no problem, but the TTY for the NMEA output does not show any data. I am clearly receiving a GPS signal (13 satellites) and am locked onto it, but I cannot figure out why I am not able to see the stream of NMEA output.
I have tried re-enabling some of the USB/UART ports to see if this would re-enable the NMEA output, but unfortunately I am still not seeing any output from the USB NMEA port.
My Current Setting: AT+QCFG=“usbcfg”,0x2C7C,0x0801,1,1,1,1,0,0,0
I have also moved the RM520N-GL card to a case that is M.2 to USB / Ethernet (Waveshare Case) and enabled the PCIe Root Complex mode to see if this would make any difference but I am still not seeing any data from the USB NMEA port.
WARNING:warning:: This AT command is very dangerous, and incorrect input may have serious consequences. Please double check before entering the command!!
First, thank you @qows for responding and providing me another avenue to investigate.
The configuration from the AT Command reference (posted by @qows) is not aligned with what Quectel has provided me previously for the RM520N-GL. The below image is what I received from Quectel a week ago. The difference from the image posted by @qows is an additional “LOG” port. If the AT+QCFG=“usbcfg” from @qows is applicable to the RM520N-GL, this would obviously throw off the alignment of ports I have been enabling / disabling.
I will give this a try, but I’d also really like to get feedback from Quectel on which implementation for AT+QCFG=“usbcfg” is correct for the RM520N-GL with Firmware: RM520NGLAAR01A08M4G_01.205.01.205. I have to assume the one sent to me by Quectel from the RG520N-EU&RM520N-GL_UAC_Application_Note must be accurate and applicable to the RM520N-GL unless this has been updated in the latest firmware and the documentation simply hasn’t caught up yet.
Upon closer inspection, I can see the suggested description for AT+QCFG=“usbcfg” from @qows can’t be applicable to the RM520N-GL. This does not include the NET (or Network port). Sometimes new configurations are added in updated firmware, and the documentation can take a while to catch up, so it’s sometimes good to review other devices’ AT command references, but in this case, it simply can’t be applicable.
Thank you again for the suggestion. My search continues…
As the original poster, I wanted to clarify. I am using an RM520N-GL card.
This is a FreeBSD machine I am using so the port names are going to be a bit different from Linux.
My AT port is /dev/cuaU0.2 and this is working just fine using minicom to access the device.
My NMEA port should be /dev/cuaU0.1, however nothing is output on this interface.
I really need to figure out what misconfiguration I have that is not allowing the NMEA output from the /dev/cuaU0.1 interface.
Can I get some support on this? I opened this question 6 days ago and I don’t have a response from Quectel that addresses my original issue. Can I pay for support to get this issue addressed??
Why is the module not outputting any data on the NMEA tty???
So the solution here is that I needed to set the data_interface to 0,0 (e.g. AT+QCFG=“data_interface”,0,0
This still allows me to use the Ethernet port while outputting the NMEA sentences on the USB-NMEA port.
To my surprise this doesn’t cause the Network interface to also appear over the USB bus. All network traffic is still directed to the Ethernet and no additional networking port shows up on the USB connection. This is exactly what I needed.
WARNING:warning:: This AT command is very dangerous, and incorrect input may have serious consequences. Please double check before entering the command!!
