Mobile broadband modem
A number of mobile phone carriers around the world offer internet access via mobile broadband (e.g. LTE, UMTS, EDGE, GSM, etc.).
This article focuses on mobile broadband modems in the format of portable USB devices and mini PCIe cards. For standalone mobile broadband routers, simply connect to them using an interface they provide (e.g. Ethernet or Wi-Fi).
Device identification
Examine the output of:
$ lsusb
which will show the vendor and product IDs of the device. Note that some devices will show two different product IDs at different times as explained below.
lsusb instead of lspci.Mode switching
From mass storage mode
Often these devices will have two modes (1) USB flash memory storage (2) USB modem. The first mode, sometimes known as ZeroCD, is often used to deliver an internet communications program for another operating system and is generally of no interest to Linux users. Additionally some have a slot into which the user can insert an additional flash memory card.
A useful utility for switching these devices into modem mode is usb_modeswitch. It ships with udev rules /usr/lib/udev/rules.d/40-usb_modeswitch.rules that contain entries for many devices, which it will switch to modem mode upon insertion.
When a device is switched, its product ID may change to a different value. The vendor ID will remain unchanged. This can be seen in the output of lsusb.
Some devices are supported in the USB serial kernel module called option (named after the "Option" devices, but not limited to just those) and may be used without usb_modeswitch.
From router mode
Depending on the device, it may expose an Ethernet network interface or provide Wi-Fi. In that case you will need to have the interface up. If the device has a DHCP server, you can use a DHCP client to match it. Otherwise, you will have to have some knowledge about the network the device expects. Such information might be obtained from its behavior in another OS. Or by searching the web. Or from the drivers, and other information, stored in the initial USB flash memory storage (ZeroCD). Some Huawei HiLink devices, for example, sometime operate at 192.168.8.0/24, with a gateway at 192.168.8.1. They also might have a web interface at http://192.168.8.1.
Modem mode
In general, at this point you should note if mode switching left you with additional /dev/ttyUSB* serial device and a network interface. You can do that with journalctl or by shell commands such as:
$ ls /dev/ttyUSB* $ ip link
Remove the PIN
First of all use your SIM card in a normal phone and disable the PIN request if present. If the SIM card asks the PIN wvdial will not work.
Failing that, you can use mmcli (provided by ) or AT commands, to unlock the SIM card.
Using mmcli
First, list the modems and find the modem's index:
$ mmcli -L
Look for /org/freedesktop/ModemManager1/Modem/MODEM_INDEX.
Find the SIM card index:
$ mmcli -m MODEM_INDEX
Just as with the modem index, look for .
Unlock the SIM card:
$ mmcli --sim=SIM_INDEX --pin=PIN
Remove the requirement for PIN:
$ mmcli --sim=SIM_INDEX --pin=PIN --disable-pin
Using AT commands
Follow the instructions in https://unix.stackexchange.com/a/313878.
Connection
To connect to the mobile network, use one of the following methods.
ModemManager
Install and usb_modeswitch.
Use to communicate with the modem.
The simplest way to establish a connection is to use mmcli's option.
First, list the modems and find the modem's index:
$ mmcli -L
Look for /org/freedesktop/ModemManager1/Modem/MODEM_INDEX.
Next connect to the mobile network. For example:
$ mmcli -m MODEM_INDEX --simple-connect="apn=internet.myisp.example"
Replace with your ISP's provided APN. If a user name and password is required, set them accordingly:
$ mmcli -m MODEM_INDEX --simple-connect="apn=internet.myisp.example,user=user_name,password=password"
To disconnect from the mobile network run:
$ mmcli -m MODEM_INDEX --simple-disconnect
See also mmcli(1) § EXAMPLES.
NetworkManager
NetworkManager uses ModemManager to work with mobile broadband modems. See NetworkManager#Mobile broadband support.
libmbim
Install libmbim. To bring up the modem you can use which is a wrapper for calls. First create a profile for mbim-network.
Now connect to the network with:
# mbim-network /dev/cdc-wdmX start
Then follow Network configuration to bring up the interface and get an IP address using DHCP.
pppd
pppd can be used to configure 3g connections. Step by step instruction is available on 3G and GPRS modems with pppd. Optionally, can be used to simplify the pppd configuration using dialog interface.
wvdial
See main article: wvdial
netctl
Netctl can be used to establish a connection using a USB modem. An example configuration file provided by is located at . Minimally you will probably have to specify
/etc/netctl/mobile_ppp
Interface=cdc-wdmX Connection=mobile_ppp AccessPointName=apn=internet.myisp.example
See the netctl article and for more information.
Tips and tricks
Disable mode switching
Some ways to disable usb_modeswitch from operating on a device before the device was inserted, for example to be able to read the initial flash memory (ZeroCD), are:
With a udev rule
Masking the udev rule the package is using can be achieved with
# ln -s /dev/null /etc/udev/rules.d/40-usb_modeswitch.rules
AT commands
There are some useful commands:
- - the device is only Modem
AT^U2DIAG=1- device is in modem mode + CD ROM- - the device in modem mode + CD ROM + Card Reader
- - the device in modem mode + Card Reader
- - enter PIN-code
- - USSD request, result can be found (probably) in .
Encode to PDU format:
$ perl -e '@a=split(//,unpack("b*","*100#")); for ($i=7; $i < $#a; $i+=8) { $a[$i]="" } print uc(unpack("H*", pack("b*", join("", @a))))."\n"'
Decode from PDU format:
$ perl -e '@a=split(//,unpack("b*", pack("H*","AA180C3602"))); for ($i=6; $i < $#a; $i+=7) {$a[$i].="0" } print pack("b*", join("", @a)).""'
Answer decoding (this example is balance response: 151.25):
$ perl -e 'print pack("H*", "003100350031002C003200350020044004430431002E0020");'
Some operators return USSD result in PDU encoding, so you should check proper decoding method.
- - get signal quality ()
- - get manufacturer
AT+GMM- get model- - get revision
- - get IMEI
- - get operator info
- - unlock modem. NCK-code should be calculated by IMEI. After that modem can work with any GSM-provider.
- - System Config
Mode:
2Automatic search- 2G ONLY
- 3G ONLY
- No change
Order:
- Automatic search
- 2G first, then 3G
23G first, then 2G- No change
Band:
80GSM DCS systems- Extended GSM 900
- Primary GSM 900
- GSM PCS
400000WCDMA IMT 2000- Any band
- No change of band
Roaming:
- Not supported
- Roaming is supported
2No change
Domain:
- CS_ONLY
- PS_ONLY
2CS_PS- ANY
- No change
Monitor used bandwidth
Frequently a 3G connection obtained via a mobile phone operator comes with restricted bandwidth, so that you are only allowed to use a certain bandwidth per time (e.g. 1GB per month). While it is quite straight-forward to know which type of network applications are pretty bandwidth extensive (e.g. video streaming, gaming, torrent, etc.), it may be difficult to keep an overview about overall consumed bandwidth.
A number of tools are available to help with that. Two console tools are , which allows to keep track of bandwith over time, and to monitor bandwidth of individual sessions. If you are a KDE user, might help.
The internal web server found in some devices, such as some Huawei HiLink, might also show information about bandwidth usage.
With dedicated software
This was tested on a Huawei EM770W (GTM382E) 3g card integrated into an Acer Aspire AS3810TG laptop. Install gnokiiAUR, then:
$ mkdir -p $XDG_CONFIG_HOME/gnokii
Usually the configuration directory is .
$ cp /etc/gnokiirc ~/.config/gnokii/config
Edit as follows:
port = /dev/ttyUSB0
You may have to use a different port depending on your configuration, for example or something else:
model = AT connection = serial
You need to be part of the group to use .
Then launch gnokii:
$ xgnokii
Click on the "SMS" icon button, a window opens up. Then click: "messages->activate sms reading". Your messages will show up in the window.
Command line script:
A small command line script using gnokii to read SMS on your SIM card (not phone memory) without having to start a GUI:
$ gnokii --getsms SM 0 end 2>&1|grep Text -A1 -B3|grep -v Text
What it does:
Granted this does not work very well if your SMS contains the word "Text", but you may adapt the script to your liking.
Another option is to use
With email like web interface
Some Devices, such as some Huawei HiLink, include an email like web interface for SMS. It is included in the device internal web server, which is used for other purposes too.
Writing SMS
You may need give permission by creating file with content like
/etc/polkit-1/rules.d/49-nopasswd_mmcli.rules
polkit.addRule(function(action, subject) {
if (action.id == "org.freedesktop.ModemManager1.Messaging" &&
subject.isInGroup("uucp"))
{
return polkit.Result.YES;
}
});
Commands to restart the device
Unplugging, and plugging, the device is sometimes used to restart the USB device. The following describes how to do that from the shell. Doing that from the shell might be useful, if, for example, the plug is at the rear side of the PC. The method described is not just for USB modems. It should be good for many other USB devices.
The important part is that the requirements are for the USB bus, and the port, the device is attached to. There could be one, or more, sub ports too. Suppose I obtained bus 2 and port 4, without sub ports, for my device from the output of . This information is also recorded in the journal. With
$ cat /sys/bus/usb/drivers/usb/2-4/product
I can verify it is the intended device.
The following sequence will restart the device: Some more comments are at, for example, https://askubuntu.com/questions/1036341/unplug-and-plug-in-again-a-usb-device-in-the-terminal.
Troubleshooting
Connection halts after few minutes running
This problem commonly occurs on some modems which locked by a mobile operator. You can successfully connect to the internet but after few minutes connection halts and your modem reboots. That happens because an operator built a some checks into modem firmware so a modem checks if a branded software is running on your pc, but usually that software is Windows-only, and obviously you do not use it. Fix (it works on ZTE-mf190 at least) is simple - send this command through serial port (use minicom or similar soft):
AT+ZCDRUN=E\r\n
This command will delete a file in the modem's filesystem - it will disable such checks.
Another possibility for such disconnections is to help the customer save bandwidth, which might be expensive. With Huawei HiLink devices with a web interface, there might be an option there to set a longer period of inactivity before the connection hangs up.
Low connection speed
Someone claims that the connection speed under Linux is lower than Windows . This is a short summary for possible solutions which are not fully verified.
In most of conditions, the low speed is caused by bad receiver signals and too many people in cell. But you still could use the following method to try to improve the connection speed:
- QoS parameter can be set with the and
AT+CGEQREQcommands. It should also be possible to decrease and limit the connection speed. Add the following command in :
Init6 = AT+CGEQMIN=1,4,64,640,64,640 Init7 = AT+CGEQREQ=1,4,64,640,64,640
- Baud parameter in could be used to increase the connection speed:
Baud = 460800
It is advisable to see the baud rate set by the official modem application for Windows (possibly on Vista).
Fix image quality
If you are getting low quality images while browsing the web over a mobile broadband connection with the hints and shift+a improves the quality of all images on this page, follow these instructions:
Install .
Edit and insert the following two lines:
AddHeader "Pragma" "No-Cache" AddHeader "Cache-Control" "No-Cache"
Configure your browser to use as a proxy server and you are all done. This is especially useful if you are using, for example, Google Chrome which, unlike Firefox, does not allow you to modify the Pragma and Cache-Control headers.
ModemManager does not recognize the modem
In case ModemManager does not recognize the modem, check the unit status of . If you get error messages such as and , you may have to whitelist your device using the ModemManager filter rules.
FCC locking
The FCC lock is a software lock integrated in WWAN modules shipped by several different laptop manufacturers like Lenovo, Dell, or HP. This lock prevents the WWAN module from being put online until some specific unlock procedure (usually a magic command sent to the module) is performed.
Since release 1.18.4, the ModemManager daemon no longer automatically performs the FCC unlock procedure .
ModemManager will keep on providing support for the known FCC unlock procedures, but no longer automatically: the user must install and select the FCC unlock procedure needed in the specific laptop being used. This applies to: EM7355, MC8805, MC7355, EM7455, SDX55, EM120.
The modemmanager package ships several scripts installed under /usr/share/ModemManager/fcc-unlock.available.d and named as with either the PCI or USB vendor and product IDs. However, they are not used if they are not in the directory.
For each device the can be found in the brackets at the end of the line:
# lspci -nn
To enable unlock script for the device it must be symlinked like so:
# ln -sft /etc/ModemManager/fcc-unlock.d /usr/share/ModemManager/fcc-unlock.available.d/vid:pid
For a Quectel EM120 modem that would be:
# ln -sft /etc/ModemManager/fcc-unlock.d /usr/share/ModemManager/fcc-unlock.available.d/1eac:1001
See the ModemManager documentation for more information.
NetworkManager: Device not available / rfkill block
If NetworkManager persists on that the device (e.g. /dev/cdc-wdm0) is not available while ModemManager can use it, it could either be, that the device is blocked using a hardware switch, by rfkill or just NetworkManager believes that.
Check rfkill with:
# rfkill ID TYPE DEVICE SOFT HARD 0 bluetooth tpacpi_bluetooth_sw unblocked unblocked 1 wwan tpacpi_wwan_sw unblocked unblocked 2 wlan phy0 unblocked unblocked 8 bluetooth hci0 unblocked unblocked
The wwan device should be listed as unblocked for both SOFT & HARD. If it is HARD blocked, a hardware switch blocks the device. If it is SOFT blocked, unblock it using:
# rfkill unblock wwan
If NetworkManager still declares the device not available, it could be that NetworkManager is not synced with rfkill. Check that using:
$ nmcli radio WIFI-HW WIFI WWAN-HW WWAN enabled enabled enabled enabled
If WWAN is listed as disabled, enable it using:
$ nmcli radio wwan on