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HMM Modem

Overview⚓︎

The Host Monitor Mini comes with a global LTE modem from Quectel with a GPS receiver (EG21 or EG25).

Starting/Enabling modem⚓︎

The modem is turned off by default. To enable it, set the GPIO named:

    MODEM_ENABLE_ON
    MODEM_RESET
    MODEM_STATUS_ON,
    MODEM_RECOVERY_ENABLE

To find out if the modem is on, read the MODEM_STATUS_ON GPIO.

gpioget $(gpiofind MODEM_STATUS_ON)
0 # means it is ON

Set MODEM_ENABLE_ON to 1: 

gpioset $(gpiofind MODEM_ENABLE_ON)=1

  • The modem takes about 10 seconds to start and register itself with the kernel. It then takes up to one minute before it is registered in the linux usb list.
  • Check USB TTY device to see if it has shown up.
find /dev -name "ttyUSB*"

/dev/ttyUSB3
/dev/ttyUSB2
/dev/ttyUSB1
/dev/ttyUSB0
  • The modem also shows up with the lsusb command.
lsusb | grep Quectel
Bus 001 Device 006: ID 2c7c:0125 Quectel Wireless Solutions Co., Ltd. EC25 LTE modem

Production settings (default)⚓︎

  • Sim card detect
  • AT+QSIMDET=1,0
    • Need restart to take affect
  • GPS (not confirmed if it is persistant)
  • AT+QGPSCFG="autogps",1
  • AT+QGPSCFG="nmeasrc",1

Test SIM card⚓︎

GPS⚓︎

Use WvDial to get a broadband connection⚓︎

Set modem into recovery mode⚓︎

Additionally, this platform can put the modem in recovery mode for forcible software updates using the MODEM_RECOVERY_ENABLE pin. This mode can also been enabled by AT commands. Use the QFirehose application compiled for aarch64 to update the modem firmware.