Mobile connection Disconnected

[perni]

Hi.

From time to time my RUT240 disconnects from the mobile network. Does anyone know why this happens or what I can search for.

Factory reset gets it back up but I do not understand why it gets disconnected.

[Matas]

Hello!

There are various of reasons as to why disconnections could happen, to name a few of them..

• Bad signal strengths - low RSRP/RSRQ values may cause dropouts.
• SIM-related issues – wrong APN, SIM PIN enabled, or operator network rejection. Possible issues from the operators end as well. I’ve had cases where clients were using SIM cards that no longer had any data left in them.
• Data/SMS limits - if mobile data limit is reached, connection is terminated.
• Network conditions - operator black/white list or roaming settings preventing reconnection.
• Connection monitoring actions - Ping Reboot, Wget Reboot, or LCP checks triggering resets when the target is unreachable.
• SIM auto-switch - if enabled, the router may drop the current SIM to switch to another under “no network” or “data connection fail” conditions.

And the list goes on.. For your case specifically, there are a few things that I would like clarification with:

1. What environment is the device being used in and what is the use case of the device?
2. What kind of SIM card is it, and what’s the provider & country (if you’re comfortable sharing this information)
3. What kind of antennas and power supply are you using with our RUT240?
4. Does anything specific happen when the mobile disconnections occur? How often do they happen? Do you see any error messages pop up, such as “EMS Reject” or “Internal modem unreachable”?
5. What’s the firmware version you’re currently running on your device?
6. Does your provider require a custom APN for your SIM card? Does the SIM need a PIN code?
7. Do you have anything such as VPN, auto-reboot, firewall configurations on your device?

Regards,
M.

[perni]

Hello
To answer you questions i’ll try to keep short.

1. Residential use in an apartment in central stockholm. Normal use of a student.
2. Simcard is a data card from swedish operator 3.
3. Antennas and power supply used is the ones that shops with the RUT240.
4. Problem arises when the device is in Stockholm and not when located at another location. This leads me to think we have a bad signal situation. But in the middle of Stockholm 4G coverage should be good, unless it is saturated.
5. I use latest firmware RUT2_R_00.07.06.19 and internal modem firmware EC25ECGAR06A04M1G_01.004.01.004
6. Auto APN works fine and I have disabled the PIN code
7. I have the ZeroTier package installed and activated.

Looking at RealTime data and especially the RSRP number that is -103dB leads me to believe that we have some kind of signal problem.

[Matas]

Hello,

@perni

Looking at RealTime data and especially the RSRP number that is -103dB leads me to believe that we have some kind of signal problem.

Very well looks to be the case. Since it looks like you’re connected to the B20 band and it provides such weak signal strengths, could you try locking onto different bands to test to see if those provide better signal strengths? Here’s a guide on band locking: Band Lock - Teltonika Networks Wiki

@perni

Problem arises when the device is in Stockholm and not when located at another location. This leads me to think we have a bad signal situation. But in the middle of Stockholm 4G coverage should be good, unless it is saturated.

This part specifically is what caught my eye, since you are in central Stockholm, it is very likely that the specific B20 (maybe some other band as well) is being used by a lot of different devices around the city, naturally making it less of a good option to use.

Regards,
M.