6.2 Modem Connection

Guidance to verify the physical connections and virtual interfaces of the mobile modem device.

6.2.1 - Physical Connections

Use the included tool hex wrench to lose all of the four pieces hexagon bolts on the front side of the EZR23 router then open the case. You can find the Mobile Modem, on the top left corner on the below image.
The Quectel mobile modem has three IPEX connectors, including Main, GNSS, and DIV. The Main connector goes to the main mobile antenna on the top left side, and the DIV connector goes to the alternative mobile antenna on the top right side. Both of them use thinner jumper cables, comparing with the Wi-Fi antenna cables.
‌ To ensure the mobile modem installed correctly, check the below subjects:
  • Check if above Main & Div sockets connect to the correct mobile antennas.
  • Check if the attached jumper cables connect tightly.
  • Check if the two pieces screws nearby the jumper cable installed correctly.
  • Touch the top cover on the mobile modem and test if its too hot temperature.
*GNSS socket is for connecting to a GPS antenna. *On Sierra Wireless modems, the alternative mobile socket is AUX, and the GPS antenna socket is GPS.
To avoid distort or break the IPEX connectors on the mobile modem, do not reconnect the jumper cables unless the router is malfunctioning.

6.2.2 - Virtual Interfaces

When the mobile modem correctly installed and the router is powered on, go to command-line interface to check the virtual interfaces created by the mobile modem. The Mobile interface uses one of the virtual interfaces to set up the internet connection.
After accessing the command-line interface, use command ls /dev to check all the virtual interfaces on the EZR23 router. Check the return value and find if the router has below two interfaces. If unable to locate these interfaces, recheck the above 6.2.1 physical connections.
  • cdc-wdm0: Use by the QMI-cellular protocol
  • ttyUSB2: Use by the 4G-PPP protocol
bus memory_bandwidth mtd4ro mtdblock5 random ttyS15 ttyUSB1
cdc-wdm0 mtd0 mtd5 mtdblock6 shm ttyS2 ttyUSB2
console mtd0ro mtd5ro net tty ttyS3 ttyUSB3
cpu_dma_latency mtd1 mtd6 network_latency ttyS0 ttyS4 urandom
full mtd1ro mtd6ro network_throughput ttyS1 ttyS5 watchdog
gpiochip0 mtd2 mtdblock0 null ttyS10 ttyS6 zero
gpiochip1 mtd2ro mtdblock1 port ttyS11 ttyS7
hwrng mtd3 mtdblock2 ppp ttyS12 ttyS8
kmsg mtd3ro mtdblock3 ptmx ttyS13 ttyS9
log mtd4 mtdblock4 pts ttyS14 ttyUSB0