Losing Internet connection after receiving incoming phone call

oleuzop · Sat Feb 13, 2021 12:21 pm

Hi everybody,

I recently purchased a LHGG LTE6 Kit and it works quite well.

I'm using it with a regular SIM card with data plan (and phone calls)

For whatever reason, whenever receiving incoming calls into the phone number the connection fails. I'm not sure if it's a problem of LTE or routing itself, since I've checked the logs and haven't seen any error on the LTE interface.

The logs for LTE interface. The call received was at 11h07m37

11:00:04 interface,info lte1 link up 
11:02:28 system,info,account user admin logged in from 192.168.88.252 via web 
11:02:28 system,info,account user admin logged in via local 
11:02:50 system,info,account user admin logged in via local 
11:03:19 system,info,account user admin logged out via local 
11:05:21 system,info,account user admin logged in via local 
11:07:37 lte,async,raw lte1: +CREG: 1,"67e8","03f7a51f",7 
11:07:37 lte,async,raw lte1: $CREG: 1,"67e8","03f7a51f",7,"17a" 
11:07:37 lte,async,raw lte1: +CEREG: 1,"67e8","03f7a51f",7 
11:07:39 lte,async,raw lte1: sent AT+CFUN? 
11:07:39 lte,async,raw lte1: rcvd +CFUN: 1 
11:07:39 lte,async,raw lte1: sent AT+COPS? 
11:07:39 lte,async,raw lte1: rcvd +COPS: 0,2,"21407",7 
11:07:40 lte,async,raw lte1: +CEREG: 1,"67e8","03f7a51e",7 
11:07:40 lte,async,raw lte1: +CREG: 1,"67e8","03f7a51e",7 
11:07:40 lte,async,raw lte1: $CREG: 1,"67e8","03f7a51e",7,"17a" 
11:07:42 lte,async,raw lte1: sent AT+CFUN? 
11:07:43 lte,async,raw lte1: rcvd +CFUN: 1 
11:07:43 lte,async,raw lte1: sent AT+COPS? 
11:07:43 lte,async,raw lte1: rcvd +COPS: 0,2,"21407",7

I'm using the lastest RouterOS 6.48.1 and almost the latest modem firmware:

[admin@MikroTik] > /interface lte info lte1 once        
           pin-status: ok
  registration-status: registered
        functionality: full
         manufacturer: "MikroTik"
                model: "R11e-LTE6"
             revision: R11e-LTE6_V025

Anyone can throw a little light on this? Any idea where else to look for errors / logs?

Thanks in advance!

Tomás

J3SN · Tue Nov 09, 2021 5:39 pm

Hi Tomás,

What probably happens is that the modem switches to GSM or 3G mode when there is an incoming call. When in GSM or 3G mode you won't be able to use the LTE connection. If there is no, or not enough, coverage in your area on GSM or 3G your data connection will drop out, or be so slow compared to the "regular" LTE connection. You can see what's happening if you login to your device with winbox, double click on the LTE interface and open the tab "Cellular". Notice what happens with the Access Technology field when there is no call, and when tere is an incoming call. If you only want to use the LTE connection for data then you can uncheck the Network Mode GSM and 3G under the General tab in the same window or use the following command:

/interface lte set lte1 network-mode=lte

Please note that if you turn off GSM and 3G, you can no longer use the SMS functionality.

Losing Internet connection after receiving incoming phone call

Losing Internet connection after receiving incoming phone call

Re: Losing Internet connection after receiving incoming phone call

Who is online