SOLVED[4G Modem (Qualcomm) Ubuntu 18.04 and CentOS 7]

Issues related to configuring your network
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oggw
Posts: 2
Joined: 2018/07/26 13:00:25

SOLVED[4G Modem (Qualcomm) Ubuntu 18.04 and CentOS 7]

Post by oggw » 2018/07/26 13:07:17

I am making a project where I have connected a 4G modem with mini-PCIe (USB-pins). In Ubuntu 18.04 I am able to connect to the internet with ModemManager and NetworkManager. Now I want to do it in CentOS 7. For some reason, it does not work. The only error I get when using ModemManager "Could not connect to Modem; Timeout was reached". According to the debug-log it says "status: 'connected' reconfiguration_required = 'no'.

The device is accepted by the kernel as /dev/cdc-wdm0. Everything is exactly like in Ubuntu 18.04 but won't connect. I have talked to the ISP and they confirm that the SIM-card is connected and registered. I asked, "Has this phone number been active today?". The answer was "Yes, most of the day. But not much data has been transferred".

What could be the reason that Ubuntu is working while CentOS is not?. The signal quality is good. The modem does not accept AT-commands. The Modem is not recognized as a mass-storage so I don't need usb_modeswitch.

Any ideas how to proceed? Are there a significant difference between Ubuntu 18.04 and CentOS 7 regarding 4G Modem connected through USB.
Last edited by oggw on 2018/07/27 08:47:29, edited 1 time in total.

oggw
Posts: 2
Joined: 2018/07/26 13:00:25

Re: 4G Modem (Qualcomm) Ubuntu 18.04 and CentOS 7

Post by oggw » 2018/07/27 08:45:42

Solved the problem with CentOS 7.
I was not able to connect with ModemManager CLI. For some reason, it did not get an IP-address (DHCP) and DNS.

sudo ifconfig wwp0s20f0u6i4 up

sudo qmicli -d /dev/cdc-wdm0 –dms-set-operating-mode=online

dhclient -d -4 wwp0s20f0u6i4

Edit /etc/resolv.conf and add the following:
nameserver 8.8.8.8

This will fix the DNS-problem.

In Ubuntu 18.04 the DNS and DHCP came automatically.

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