Skip to main content

4G/5G

This section introduces how to use the M.2 B KEY interface functions on the Raspberry Pi, laying the foundation for subsequent project development.

danger
  • The test uses the SIM7600. If using other modules, refer to the corresponding 4G/5G module's Wiki.
  • The board itself does not support 4G/5G; the module must be connected via the M.2 B KEY interface. The M.2 B KEY interface provides only a USB2.0 channel and does not support PCIe devices.
warning
  • To turn off the 4G/5G module, use GPIO6 (BCM pin 6). Output high to disable the module, output low to enable it.
  • Enabling or disabling the module takes some time (approximately 30 seconds).

Troubleshooting​

No New ttyUSB Device Detected​

  • Execute the following commands in the terminal to load the USB device descriptors: 
    sudo modprobe option
    sudo sh -c 'echo "1e0e 9011" > /sys/bus/usb-serial/drivers/option1/new_id'
    sudo sh -c 'echo "1e0e 9018" > /sys/bus/usb-serial/drivers/option1/new_id'
    sudo sh -c 'echo "1e0e 901E" > /sys/bus/usb-serial/drivers/option1/new_id'

Setting Up AT Command Configuration Environment​

  • Install the text-based serial communication tool minicom:

    sudo apt-get install minicom

  • Connect to the 4G/5G module port (use ttyUSB2, which appears when the module is connected; adjust the port according to your actual situation):

    sudo minicom -D /dev/ttyUSB2

  • The following AT commands are common to both 4G and 5G modules:

    CommandDescriptionReturn Value
    ATTest commandOK
    ATEATE1 enables echo
    ATE0 disables echo    		OK
    AT+CGMIQuery module manufacturerOK
    AT+CGMMQuery module modelOK
    AT+CGSNQuery product serial numberOK
    AT+CSUBQuery module version and chipOK
    AT+CGMRQuery firmware version serial numberOK
    AT+IPREXSet module hardware serial port baud rate +IPREX:OK
    AT+CRESETReset moduleOK
    AT+CSQQuery network signal quality; returns signal value +CSQ: 17,99OK
    AT+CPIN?Query SIM card status; returns READY if the SIM card is recognized properly+CPIN: READY
    AT+COPS?Query current operator; returns operator information when connected to the network +COPS:OK
    AT+CREG?Query network registration status +CREG:OK
    AT+CPSI?Query UE system information
    AT+CNMPNetwork mode selection command:
    2: Automatic
    13: GSM only
    38: LTE only
    48: Any modes but LTE
    ... ....    		OK

ifconfig Fails to Find the Device​

  • Click here to set up the AT command configuration environment
  • Compare the newly added ttyUSB interfaces (if the new interfaces are ttyUSB0~ttyUSB4). If no new ttyUSB device appears, click here to configure.
  • Use the newly added ttyUSB interface for configuration changes (here we use the newly added ttyUSB2): 
    sudo minicom -D /dev/ttyUSB2
  • Enter the following command and press Enter. The module will automatically restart to apply the settings (adjust according to your module's requirements; different modules support different dial-up methods; the example below uses Qualcomm's RNDIS dial-up).
  • This command only needs to be set once. On the next power-up, the module will default to this mode (1E0E: Vendor ID, 9011: depends on the actual module): 
    AT+CUSBCFG=USBID,1E0E,9011
    Various module setting parameters
  • Rescan the devices: 
    ifconfig

4G/5G Usage​

  • Connect the 4G/5G module and the SIM card to the device, then power on.
  • Use ifconfig to scan for usb0 (USB network adapter – the exact device name may vary; it is not necessarily usb0). If ifconfig does not find the device, click here to troubleshoot. 
    ifconfig
    Scan 4G/5G modules
  • If the SIM card is properly connected, the NET LED blinks normally but no IP address is obtained, verify that the SIM card is working.
  • If the SIM card is working but still no IP address is obtained, execute the following commands in the terminal to renew the IP address: 
    sudo dhclient -v usb0
    sudo apt-get install udhcpc
    sudo udhcpc -i usb0
    sudo route add -net 0.0.0.0 usb0
  • Test whether the wireless network card can ping Baidu successfully; be sure to connect the antenna. 
    ping -I usb0 www.baidu.com  # Here the port added by the 4G/5G module is usb0; adjust the command according to your actual situation
  • If you are using an IoT SIM card that successfully registers on the network but dial-up fails and ping does not work, try one of the following AT commands to select the optimal frequency band (click here to set up the AT command configuration environment): 
    AT+CNBP=0x0002000000400183,0x000001E000000000,0x0000000000000021
    AT+CNBP=0x0002000000400180,0x480000000000000000000000000000000000000000000042000001E200000095,0x0000000000000021