Support for Teltonika RUT955 LTE Modem EC25-EU

Morning,

Since batch at least 113 Teltonika RUT955 is shipped with a new, to my understanding not supported LTE modem: Quectel EC25-EU.

The other devices I have is from batch 107 and is shipped with Quectel EG25-G and works just fine.

The modem hardware replacement are currently breaking problems for the large amount of devices >100 we ordered. I've tested this on 21.02.03 and with any WWAN driver I can think of.

The modem works on stock firmware from Teltonika but we cannot use that one.
https://wiki.teltonika-networks.com/view/RUT955_Firmware_Downloads

EC25-EU on OpenWRT 21.02.03

root@OpenWRT-RUT955:~# dmesg
[   17.306552] qmi_wwan 1-1.4:1.4: cdc-wdm0: USB WDM device
[   17.323300] qmi_wwan 1-1.4:1.4 wwan0: register 'qmi_wwan' at usb-1b000000.usb-1.4, WWAN/QMI device, 92:14:1c:8a:86:5f
[   17.334401] usbcore: registered new interface driver qmi_wwan
[   17.616697] usbcore: registered new interface driver option
[   17.622530] usbserial: USB Serial support registered for GSM modem (1-port)
[   17.630586] option 1-1.4:1.0: GSM modem (1-port) converter detected
[   17.637326] usb 1-1.4: GSM modem (1-port) converter now attached to ttyUSB0
[   17.644882] option 1-1.4:1.1: GSM modem (1-port) converter detected
[   17.651649] usb 1-1.4: GSM modem (1-port) converter now attached to ttyUSB1
[   17.659190] option 1-1.4:1.2: GSM modem (1-port) converter detected
[   17.665947] usb 1-1.4: GSM modem (1-port) converter now attached to ttyUSB2
[   17.673486] option 1-1.4:1.3: GSM modem (1-port) converter detected
[   17.680257] usb 1-1.4: GSM modem (1-port) converter now attached to ttyUSB3

EC25-EU on stock firmware

root@Teltonika-RUT955:~# dmesg
[   21.840000] usb 1-1.4: new high-speed USB device number 4 using ehci-platform
[   21.960000] option 1-1.4:1.0: GSM modem (1-port) converter detected
[   21.960000] usb 1-1.4: GSM modem (1-port) converter now attached to ttyUSB0
[   21.970000] option 1-1.4:1.1: GSM modem (1-port) converter detected
[   21.980000] usb 1-1.4: GSM modem (1-port) converter now attached to ttyUSB1
[   21.990000] option 1-1.4:1.2: GSM modem (1-port) converter detected
[   21.990000] usb 1-1.4: GSM modem (1-port) converter now attached to ttyUSB2
[   22.000000] option 1-1.4:1.3: GSM modem (1-port) converter detected
[   22.010000] usb 1-1.4: GSM modem (1-port) converter now attached to ttyUSB3
[   22.090000] qmi_wwan 1-1.4:1.4: cdc-wdm0: USB WDM device
[   22.090000] qmi_wwan 1-1.4:1.4: Quectel EC21&EC25&EC20 R2.0 work on RawIP mode
[   22.100000] qmi_wwan 1-1.4:1.4 wwan0: register 'qmi_wwan' at usb-ehci-platform-1.4, WWAN/QMI device, 06:a2:de:3c:16:a5

Any pointers? Suggestions on how to attack the problem?

I customized a large fleet of RUT955 for IoT apps, all having EC25, in following variants:

  1. EC25-A
  2. EC25-V
  3. EC25-EU
    Various Teltonika batches.
    No problems. BTW: AFAIK, usage of EG25-G is newer than EC25.
    However, I am ONLY using serial mode. Because of stability.

Teltonika uses old openwrt as basis for their stuff, which means old kernel and old packages. So there there might be some differences.

Thanks for your swift response.

Please give me some pointers on serial mode, this is new for me. Stability is what I am looking for! I've had success earlier with EC25-E Mini PCIe as well.

As your app looks like a commercial project, consultancy only on a commercial basis. Feel free to PM me.

Sadly thats where it ends then, this is for an in house project which is done on my free time. Everything looked fine until the new batch of devices was delivered.

However it gives me hope to see you managed to configure it with EC25-EU

Thanks for your early pointers!

This tells the whole story.

The EC25-EU QMI is raw-ip while the EC25-G isn't. The EC25-G will give the router an IP Address using DHCP while a raw-ip modem requires you to extract it from the modem manually. I don't believe that the uqmi code does this automatically for you although I've never looked. uqmi has a command to see if the modem uses raw-ip but you gets answers like "Yes", "No" and "Don't Know".

Running in PPP mode gets around this problem so, when specifying the interface you need to use PPP rather than QMI. This will give much slower speeds than QMI.

Other than adding the extra code to handle raw-ip your only other choices are to use PPP or MBIM.

Hi

Does not EC25-EU fully support QMI, or what happens when you try to use QMI-protocol?

uqmi does support raw-ip

uqmi -d /dev/cdc-wdm0 --wda-get-data-format
uqmi -d /dev/cdc-wdm0 --wda-set-data-format raw-ip