EM9190 : Configure module without AT commands

Hi there,

We could establish data connection in Linux Environment using MBIM interface. However, the question I have is do we need to configure network using AT commands before I use MBIM interface for the data transfer?

In other words, what is the connection between AT commands and MBIM interface?


Yes, you can use at!gstatus? To check registration status before establish data connection with mbim

ok that was helpful, thanks.

But what is the connection between AT commands and MBIM interface?

What do you mean by connection?
They are just two interfaces

Of course they are connected, if you shut down the telecom stack by AT+cfun=0, the mbim data channel cannot byle established

Alright. One more query, with the same module, same sim and same configuration, MBIM network connection fails. What could be the possible reason?

sudo mbim-network /dev/cdc-wdm0 start
Loading profile at /etc/mbim-network.conf…
APN: airtelgprs.com
APN auth protocol: unset
APN user: unset
APN password: unset
mbim-proxy: yes
Querying subscriber ready status ‘mbimcli -d /dev/cdc-wdm0 --query-subscriber-ready-status --device-open-proxy’…
[/dev/cdc-wdm0] Subscriber ready status retrieved: Ready state: ‘initialized’ Subscriber ID: ‘404940971097200’ SIM ICCID: ‘8991000920922937967F’ Ready info: ‘none’ Telephone numbers: (0) ‘unknown’
Querying registration state ‘mbimcli -d /dev/cdc-wdm0 --query-registration-state --device-open-proxy’…
[/dev/cdc-wdm0] Registration status: Network error: ‘unknown’ Register state: ‘home’ Register mode: ‘automatic’ Available data classes: ‘lte’ Current cellular class: ‘gsm’ Provider ID: ‘40440’ Provider name: ‘airtel’ Roaming text: ‘unknown’ Registration flags: ‘packet-service-automatic-attach’
Attaching to packet service with ‘mbimcli -d /dev/cdc-wdm0 --attach-packet-service --device-open-proxy’…
[/dev/cdc-wdm0] Successfully attached to packet service [/dev/cdc-wdm0] Packet service status: Network error: ‘unknown’ Packet service state: ‘attached’ Available data classes: ‘lte’ Uplink speed: ‘1200000000 bps’ Downlink speed: ‘3200000000 bps’
Starting network with ‘mbimcli -d /dev/cdc-wdm0 --connect=apn=‘airtelgprs.com’ --device-open-proxy’…
error: operation failed: Failure
Network start failed

Moreover, I’m unable to set the Mobile network settings in Linux PC. Is this causing the MBIM network connection failure?
What am I missing?


it is hard to comment why the MBIM sometimes works but sometimes not working with same module, same sim and same configuration.

Could it be signal strength?
Could it be hardware instability?
Could it be network unstable situation?

I noticed

[/dev/cdc-wdm0] Registration status: Network error: ‘unknown’ Register state: ‘home’ Register mode:

Normally when I see this error i check two things:
1/ is the modem using the correct firmware at!impref
2/ how about your apn: one thing is that is is set with mbim but what does at+cgdcont report is it the same apn as the one you have configured?



To answer your question,

  1. yes the modem is using the latest firmware
  2. The APN set in at+cgdcont is same as the one I have configured while starting the mbim.

I found out why mbim fails with the following error “Network start failed”.
Initially while setting the APN and checking the network registration, I provided AT+CGACT=1,1 command, which activates the network. Since network is already activated, giving the “sudo mbim-network /dev/cdc-wdm0 start” would result in “Network start failed”.