RUTX50 modem disconnecting on 7.22.1 + RG501QEUAAR12A11M4G

[jschwart]

Hi all, it seems I’m running into intermittent issues with the modem disconnecting:

[  505.010108] option1 ttyUSB0: GSM modem (1-port) converter now disconnected from ttyUSB0
[  505.010315] option 2-1:1.0: device disconnected
[  505.017686] option1 ttyUSB1: GSM modem (1-port) converter now disconnected from ttyUSB1
[  505.021917] option 2-1:1.1: device disconnected
[  505.029951] xhci-hcd xhci-hcd.0.auto: WARN Set TR Deq Ptr cmd failed due to incorrect slot or ep state.
[  505.034607] option1 ttyUSB2: GSM modem (1-port) converter now disconnected from ttyUSB2
[  505.043696] option 2-1:1.2: device disconnected
[  505.052364] option1 ttyUSB3: GSM modem (1-port) converter now disconnected from ttyUSB3
[  505.056079] option 2-1:1.3: device disconnected
[  505.056887] [01-serial-symlink.sh] Device ttyUSB0 at /devices/platform/soc/8af8800.usb/8a00000.usb/xhci-hcd.0.auto/usb2/2-1/2-1:1.0/ttyUSB0/tty/ttyUSB0 disappeared!
[  505.219937] qmi_wwan 2-1:1.4 wwan0: unregister 'qmi_wwan' usb-xhci-hcd.0.auto-1, WWAN/QMI device
[  505.359213] [01-serial-symlink.sh] Device ttyUSB1 at /devices/platform/soc/8af8800.usb/8a00000.usb/xhci-hcd.0.auto/usb2/2-1/2-1:1.1/ttyUSB1/tty/ttyUSB1 disappeared!
[  505.650178] [01-serial-symlink.sh] Device ttyUSB2 at /devices/platform/soc/8af8800.usb/8a00000.usb/xhci-hcd.0.auto/usb2/2-1/2-1:1.2/ttyUSB2/tty/ttyUSB2 disappeared!
[  505.659823] usb 2-1: reset SuperSpeed USB device number 2 using xhci-hcd
[  505.846757] option 2-1:1.0: GSM modem (1-port) converter detected
[  505.847230] usb 2-1: GSM modem (1-port) converter now attached to ttyUSB0
[  505.852684] option 2-1:1.1: GSM modem (1-port) converter detected
[  505.856094] [01-serial-symlink.sh] Device ttyUSB3 at /devices/platform/soc/8af8800.usb/8a00000.usb/xhci-hcd.0.auto/usb2/2-1/2-1:1.3/ttyUSB3/tty/ttyUSB3 disappeared!
[  505.859247] usb 2-1: GSM modem (1-port) converter now attached to ttyUSB1
[  505.881303] option 2-1:1.2: GSM modem (1-port) converter detected
[  505.886591] usb 2-1: GSM modem (1-port) converter now attached to ttyUSB3
[  505.893333] option 2-1:1.3: GSM modem (1-port) converter detected
[  505.899953] usb 2-1: GSM modem (1-port) converter now attached to ttyUSB4
[  505.918647] qmi_wwan 2-1:1.4: cdc-wdm0: USB WDM device
[  505.921782] qmi_wwan 2-1:1.4 wwan0: register 'qmi_wwan' at usb-xhci-hcd.0.auto-1, WWAN/QMI device, 36:46:fe:cb:8a:9c
[  506.397217] [01-serial-symlink.sh] New device ttyUSB0 at /devices/platform/soc/8af8800.usb/8a00000.usb/xhci-hcd.0.auto/usb2/2-1/2-1:1.0/ttyUSB0/tty/ttyUSB0 appeared!
[  506.696555] [01-serial-symlink.sh] New device ttyUSB1 at /devices/platform/soc/8af8800.usb/8a00000.usb/xhci-hcd.0.auto/usb2/2-1/2-1:1.1/ttyUSB1/tty/ttyUSB1 appeared!
[  507.006722] [01-serial-symlink.sh] New device ttyUSB3 at /devices/platform/soc/8af8800.usb/8a00000.usb/xhci-hcd.0.auto/usb2/2-1/2-1:1.2/ttyUSB3/tty/ttyUSB3 appeared!
[  507.225512] [01-serial-symlink.sh] New device ttyUSB4 at /devices/platform/soc/8af8800.usb/8a00000.usb/xhci-hcd.0.auto/usb2/2-1/2-1:1.3/ttyUSB4/tty/ttyUSB4 appeared!
[  525.718191] usb 2-1: USB disconnect, device number 2
[  525.718650] option1 ttyUSB0: GSM modem (1-port) converter now disconnected from ttyUSB0
[  525.722636] option 2-1:1.0: device disconnected
[  525.731364] option1 ttyUSB1: GSM modem (1-port) converter now disconnected from ttyUSB1
[  525.735068] option 2-1:1.1: device disconnected
[  525.743943] option1 ttyUSB3: GSM modem (1-port) converter now disconnected from ttyUSB3
[  525.747386] option 2-1:1.2: device disconnected
[  525.755961] option1 ttyUSB4: GSM modem (1-port) converter now disconnected from ttyUSB4
[  525.759804] option 2-1:1.3: device disconnected
[  525.763953] [01-serial-symlink.sh] Device ttyUSB0 at /devices/platform/soc/8af8800.usb/8a00000.usb/xhci-hcd.0.auto/usb2/2-1/2-1:1.0/ttyUSB0/tty/ttyUSB0 disappeared!
[  525.768945] qmi_wwan 2-1:1.4 wwan0: unregister 'qmi_wwan' usb-xhci-hcd.0.auto-1, WWAN/QMI device
[  525.995490] [01-serial-symlink.sh] Device ttyUSB1 at /devices/platform/soc/8af8800.usb/8a00000.usb/xhci-hcd.0.auto/usb2/2-1/2-1:1.1/ttyUSB1/tty/ttyUSB1 disappeared!
[  526.189574] [01-serial-symlink.sh] Device ttyUSB3 at /devices/platform/soc/8af8800.usb/8a00000.usb/xhci-hcd.0.auto/usb2/2-1/2-1:1.2/ttyUSB3/tty/ttyUSB3 disappeared!
[  526.376895] [01-serial-symlink.sh] Device ttyUSB4 at /devices/platform/soc/8af8800.usb/8a00000.usb/xhci-hcd.0.auto/usb2/2-1/2-1:1.3/ttyUSB4/tty/ttyUSB4 disappeared!
[  538.209945] usb 2-1: new SuperSpeed USB device number 3 using xhci-hcd
[  538.393410] option 2-1:1.0: GSM modem (1-port) converter detected
[  538.394114] usb 2-1: GSM modem (1-port) converter now attached to ttyUSB0
[  538.399466] option 2-1:1.1: GSM modem (1-port) converter detected
[  538.406209] usb 2-1: GSM modem (1-port) converter now attached to ttyUSB1
[  538.413147] option 2-1:1.2: GSM modem (1-port) converter detected
[  538.418686] usb 2-1: GSM modem (1-port) converter now attached to ttyUSB2
[  538.425355] option 2-1:1.3: GSM modem (1-port) converter detected
[  538.431792] usb 2-1: GSM modem (1-port) converter now attached to ttyUSB3
[  538.455113] qmi_wwan 2-1:1.4: cdc-wdm0: USB WDM device
[  538.458360] qmi_wwan 2-1:1.4 wwan0: register 'qmi_wwan' at usb-xhci-hcd.0.auto-1, WWAN/QMI device, 56:2c:92:f4:1d:9d
[  538.513612] [01-serial-symlink.sh] New device ttyUSB0 at /devices/platform/soc/8af8800.usb/8a00000.usb/xhci-hcd.0.auto/usb2/2-1/2-1:1.0/ttyUSB0/tty/ttyUSB0 appeared!
[  538.702372] [01-serial-symlink.sh] New device ttyUSB1 at /devices/platform/soc/8af8800.usb/8a00000.usb/xhci-hcd.0.auto/usb2/2-1/2-1:1.1/ttyUSB1/tty/ttyUSB1 appeared!
[  538.882114] [01-serial-symlink.sh] New device ttyUSB2 at /devices/platform/soc/8af8800.usb/8a00000.usb/xhci-hcd.0.auto/usb2/2-1/2-1:1.2/ttyUSB2/tty/ttyUSB2 appeared!
[  539.061197] [01-serial-symlink.sh] New device ttyUSB3 at /devices/platform/soc/8af8800.usb/8a00000.usb/xhci-hcd.0.auto/usb2/2-1/2-1:1.3/ttyUSB3/tty/ttyUSB3 appeared!
[  560.050944] qmi_wwan 2-1:1.4 wwan0: mode: raw IP

I read that there is a special modem firmware update available that should address this. Could this be provided? If not is there any other way to avoid this?

Many thanks in advance!

[ovo]

Hi

Downgrading fixed the issue for me

RUTX50 internal modem unstable after RG520 modem firmware update – SIM failure, gsmctl N/A, no registration

Hello, I am experiencing a persistent internal modem problem on a RUTX50 which started immediately after a modem firmware update. Before the modem update the router was working normally. The issue persists after factory reset, firmware downgrade and clean configuration. Device information Device: RUTX50 Hardware revision: 0404 Batch: 043 Manufacturing year: 2024 Router firmware tested: RUTX_R_00.07.21.2 RUTX_R_00.07.20.3 Internal modem: Quectel RG520N-EBDC Current modem firmware: R…

[heartless]

@jschwart

I read that there is a special modem firmware update available that should address this.

There is, but that firmware is not for RG501Q-EU modem that you have. There are no known issues with RG501Q-EU based devices as far as i know. They work properly. You issue is caused by something else. Its either weak signal, bad antenna connection, or some sort of miss configuration at your end or your providers end.

@ovo

Hi

Downgrading fixed the issue for me

Hello, I am experiencing a persistent internal modem problem on a RUTX50 which started immediately after a modem firmware update. Before the modem update the router was working normally. The issue persists after factory reset, firmware downgrade and clean configuration. Device information Device: RUTX50 Hardware revision: 0404 Batch: 043 Manufacturing year: 2024 Router firmware tested: RUTX_R_00.07.21.2 RUTX_R_00.07.20.3 Internal modem: Quectel RG520N-EBDC Current modem firmware: R…

This downgrade process is for RG520N based devices, not the RG501Q.

[jschwart]

Many thanks for the responses!

@heartless

Its either weak signal, bad antenna connection, or some sort of miss configuration at your end or your providers end.

These things would all seem related to the modem connection with the cell tower. The message shows the modem connection running over USB to the main router system being interrupted however. Are those not separate things?

I would not expect messages related to USB disconnections for any of the issues you mention. Even with a weak cell tower signal or bad antenna connections, the modem should not appear disconnected from the router. Or does the modem present itself differently to the router based on any properties related to the cell tower connection?

I did configure the device to only use the channels that are used here. This seems to have reduced the problem frequency quite a bit.

[heartless]

The modem in this device behaves strange where you have weak signal and antenna issues. The errors in the logs are misleading because they are pointing to non existent and completely unrelated issue. Those errors disappear when you have strong signal. Im talking from personal experience here. I used to have my RUTX50 at the location with very bad signal. I got same errors as you. Then i moved to another location where i had exceptionally strong signal on all bands, but get this. I started having “Internal modem unreachable” errors even though i had strong signal. Then i realized that my antennas were not screwed in tightly. Once ive done that, all issues were gone. And here i am today several years later running latest modem firmware and software and everything works with zero issues. Devices with RG520N modem are completely different story. They indeed have firmware problems, but your device is not using that modem.

I would recommend you to download latest RUTX50 firmware file from here and then follow these instructions for flashing. Keep in mind that this will restore device to factory defaults with latest firmware. After that, check antenna connections and make sure they are tight.

[jschwart]

@heartless

The modem in this device behaves strange where you have weak signal and antenna issues.

I think that might be something that could be addressed?

@heartless

Those errors disappear when you have strong signal.

Right now the signal is not very strong. I am still considering getting an external antenna instead. Would it make sense to try that first?

[heartless]

@jschwart

I think that might be something that could be addressed?

I think some modem issues are not really something that Teltonika can solve directly and quickly. They need to be fixed upstream by modem manufacturer Quectel. And i assume Quectel struggles as well because different countries have different providers and those providers have different configurations. Nothing is standardized when it comes to how the cell towers should be configured, and this is why its hard to produce a fix that will solve one problem without introducing new one. This is also the reason why there are people that have RUTX50 that works flawlessly, and then, there are people with same device that are literally unusable. Its a tough business for both the manufacturers and end customers.

@jschwart

Right now the signal is not very strong. I am still considering getting an external antenna instead. Would it make sense to try that first?

It can help drastically if you are using antenna from reputable manufacturer like Iskra or Poynting. However, nn locations with low signal such as yours, omnidirectional antennas are waste of money. You need something like this if you want results.

These are Iskra P60 and they are not cheap nor easy to install. Cheap antennas can make matters worse. I would recommend, just for testing, trying your device outside. You need to find exact issue before you start throwing money at the problem.

[jschwart]

@heartless

They need to be fixed upstream by modem manufacturer Quectel. And i assume Quectel struggles as well because different countries have different providers and those providers have different configurations.

Certain issues possibly, but I’d expect the Quectel firmware to have a separation between its host connection over USB and uplink cell tower connectivity to such a point that one should not affect the other. These are two separate things.

@heartless

It can help drastically if you are using antenna from reputable manufacturer like Iskra or Poynting. However, nn locations with low signal such as yours, omnidirectional antennas are waste of money.

I was thinking about an omnidirectional antenna because the router currently connects to two points, one to the north and one to the east. With a directional antenna I guess only a single point could be connected to.

@heartless

These are Iskra P60 and they are not cheap nor easy to install.

What exactly makes them hard to install?

@heartless

I would recommend, just for testing, trying your device outside. You need to find exact issue before you start throwing money at the problem.

The RUTX50 manages to connect to two towers that are quite far away in different directions. Outside the signal is always significantly better (with any device). This is why I suspect having an outdoor omnidirectional antenna would already make a big improvement.

Many thanks for looking along!!

[heartless]

@jschwart

Certain issues possibly, but I’d expect the Quectel firmware to have a separation between its host connection over USB and uplink cell tower connectivity to such a point that one should not affect the other. These are two separate things.

I know what you mean, but thats not how things work in reality unfortunately.

@jschwart

I was thinking about an omnidirectional antenna because the router currently connects to two points, one to the north and one to the east. With a directional antenna I guess only a single point could be connected to.

Omnidirectional antenna can help in your scenario where you connect to two different towers, however, with directional antenna you are hitting one cell tower but you are getting full signal from that tower which is better than connecting to two of them.

@jschwart

What exactly makes them hard to install?

Well, the fact that you need a pole, you need to drill a hole and lay down the cables is sometimes seen as very complicated thing to do by majority of people. Ive seen people that think drilling a hole throgh a concrete ceiling or wall is a huge problem for them. Let alone climbing up the roof or laying cables. If its not a problem for you, thats great. One think you need to pay special attention when it comes do directional antennas is polarisation.

This is how they should be connected to RUTX50

Thanks to @tirkiz for these images.

[jschwart]

I looked up the Iskra P-60, but it seems to be just 2x2? Would one need to buy two sets to get 4x4 MIMO? Generally I don’t think this product is sold where I am btw.

[heartless]

Yup. You need two sets.