How to change 4G modem type ethernet to gsm

snap
1

Hi,
I have a ZTE 4G modem，but it only connects through ppp not usb0. I test another Quectel 4G modem, it worked well.
My board is raspi 3. And my snap info is as follows.
Name Version Rev Tracking Publisher Notes
core 16-2.42.5 8270 stable canonical✓ core
core18 20190723 1076 stable canonical✓ base
modem-manager 1.8.0-10 270 stable canonical✓ -
network-manager 1.2.2-22 383 stable canonical✓ -
pi 18-1 17 18-pi3 canonical✓ gadget
pi-kernel 4.15.0-1052.56 66 18-pi3 canonical✓ kernel
snapd 2.42.5 5756 stable canonical✓ snapd

Quectel modem nmcli info:
xx@linux:~$ nmcli d
DEVICE TYPE STATE CONNECTION
cdc-wdm0 gsm connected China Unicom
wlan0 wifi unavailable –
eth0 ethernet unmanaged –
lo loopback unmanaged –

ZTE modem nmcli info:
xx@linux:~$ nmcli d
DEVICE TYPE STATE CONNECTION
ttyUSB1 modem connected China Unicom
usb0 ethernet unavailable –
wlan0 wifi unavailable –
eth0 ethernet unmanaged –
lo loopback unmanaged –

I think I need to change usb0 ethernet type to gsm. Can you give me some advice about that? Thank you.

2

Perhaps @abeato has some thoughts on this? Sounds like a modem-manager or network-manager question :smile:

3

Yes, it is a modem-manager question. @abeato , could you give me some advice? Thank you.

4

@smartdabao most USB stick modems that are thought for desktop users, like ZTE ones, do not need ModemManager to work. If you have one of these, they have a dhcp server on their end so you can use them directly with NetworkManager - to set cellular settings like APN they usually offer a web interface.

I would try to stop MM and bring up the usb0 interface using nmcli. If that does not work, you might need to send some AT command to the modem to activate the dhcp server (that is actually what MM does for some Quectel modems). I suggest taking a look to the modem manual in that case.

5

Thank you for your reply. You said you will stop MM, does that mean there will be only NM and no MM in the future? If I need to do some special actions on modems, I need to send AT commands to modems directly, am I right?
Another question, I am developing an IoT gateway, and it will integrate many modems of different vendors. Is it possible to control these modems with NM? Could you give me some advice? Thank you.

6

Thank you for your reply. You said you will stop MM, does that mean there will be only NM and no MM in the future? If I need to do some special actions on modems, I need to send AT commands to modems directly, am I right?

No, I am suggesting a way for you to check if it is possible to open a connection on usb0. After that you can decide if you need a specific plugin in MM for your modem or not - you are right in that you will need it if you have to issue AT commands to the modem for some reason.

Another question, I am developing an IoT gateway, and it will integrate many modems of different vendors. Is it possible to control these modems with NM? Could you give me some advice? Thank you.

Usually NM talks to MM to control modems, so you need both installed, but to create the connection you just need to control NM. See https://docs.ubuntu.com/core/en/stacks/network/network-manager/docs/configure-cellular-connections