If we have a modem in the system, we should be able to see it with mmcli -L, for instance:
$ sudo mmcli -L
Found 1 modems:
/org/freedesktop/ModemManager1/Modem/0 [BRAND] MODEL
The command shows the DBus path for the modem, with the number at the end of the path being the argument to access it from the cli:
$ sudo mmcli -m 0
/org/freedesktop/ModemManager1/Modem/0 (device id '817f7e2b3c6dfdf1d4ee7f4c4ecc34de61bc5de9')
-------------------------
Hardware | manufacturer: 'BRAND'
| model: 'MODEL'
| revision: 'FW.REVISION'
| supported: 'gsm-umts'
| current: 'gsm-umts'
| equipment id: '988037034540195'
-------------------------
System | device: '/sys/devices/pci0000:00/0000:00:01.2/usb1/1-1'
| drivers: 'option1'
| plugin: 'generic'
| primary port: 'ttyUSB3'
| ports: 'ttyUSB0 (qcdm), ttyUSB1 (at), ttyUSB3 (at)'
-------------------------
Numbers | own : 'unknown'
-------------------------
Status | lock: 'none'
| unlock retries: 'sim-pin (3), sim-puk (10)'
| state: 'disabled'
| power state: 'on'
| access tech: 'unknown'
| signal quality: '0' (cached)
-------------------------
Modes | supported: 'allowed: 2g; preferred: none
| allowed: 3g; preferred: none
| allowed: 2g, 3g; preferred: none
| allowed: 2g, 3g; preferred: 2g
| allowed: 2g, 3g; preferred: 3g'
| current: 'allowed: any; preferred: none'
-------------------------
Bands | supported: 'unknown'
| current: 'unknown'
-------------------------
IP | supported: 'none'
-------------------------
3GPP | imei: '988037034540195'
| enabled locks: 'none'
| operator id: 'unknown'
| operator name: 'unknown'
| subscription: 'unknown'
| registration: 'unknown'
-------------------------
SIM | path: '/org/freedesktop/ModemManager1/SIM/0'
-------------------------
Bearers | paths: 'none'
This shows quite a bit of information: model, ports, status and so on. There is an unlocked SIM card, but no bearer defined. Again, we use the last number in the SIM path to access the SIM information:
$ sudo mmcli -i 0
SIM '/org/freedesktop/ModemManager1/SIM/0'
-------------------------
Properties | imsi : '123450030477777'
| id : '9876075782002298987'
| operator id : '21477'
| operator name : 'my-oper'
As can be seen, status is initially ‘disabled’. To power on the modem we can do:
$ sudo mmcli -m 0 --enable --timeout=120
successfully enabled the modem
After this, the registration status should change:
$ sudo mmcli -m 0
...
-------------------------
Status | lock: 'none'
| unlock retries: 'sim-pin (3), sim-puk (10)'
| state: 'registered'
| power state: 'on'
| access tech: 'umts'
| signal quality: '32' (recent)
-------------------------
...