AirCast

150Mbps 4G LTE USB Modem Setup

What You'll Achieve

By the end of this guide, your Raspberry Pi will have a reliable 4G LTE internet connection through a USB network adapter, perfect for drone streaming in areas without WiFi.

Time needed: 20 minutes
Difficulty: Intermediate (Linux commands required)

💡 Why USB Network Mode?

  • Lower latency - Direct connection without WiFi overhead
  • More reliable - No wireless interference issues
  • Power efficient - USB provides both data and power
  • Cost effective - Only $8 on AliExpress

💰 Buy on AliExpress - Best Budget Option

150Mbps 4G LTE USB Modem

📋 Before You Start

Make sure you have everything ready:

  • USB modem - The 150Mbps 4G LTE modem from the link above
  • SIM card - With active data plan (no PIN lock)
  • Raspberry Pi - With SSH access enabled
  • Internet connection - For initial package installation

🗺️ Setup Overview

🔌

Step 1-2

Prepare Hardware

5 minutes

⚙️

Step 3-5

Configure Modem

10 minutes

🌐

Step 6-7

Connect & Test

5 minutes

🔌 Step-by-Step Setup

💡 What we're doing: We'll convert the modem from its default WiFi hotspot mode to a USB network adapter mode. This gives your Raspberry Pi direct internet access with better performance.

1

Insert SIM Card & Connect

🕒 Time: 2 minutes

Why: The modem needs a SIM card with data to provide internet.

  1. Slide the back cover downward to open
  2. Insert SIM card (gold contacts facing down)
  3. Replace cover and plug modem into Raspberry Pi USB port
  4. Wait 30 seconds for the LED to turn on

✓ Success: LED is on (solid or blinking)

⚠️ Note about APN

Most carriers use "internet" as the default APN, which this modem usually auto-configures. If you have connection issues later, you may need to set it manually via the web interface at 192.168.1.1

2

Install Required Software

🕒 Time: 3 minutes

Why: These tools let us switch the modem from WiFi to USB network mode.

SSH into your Raspberry Pi and run:

sudo apt-get update && sudo apt-get install -y usb-modeswitch usb-modeswitch-data

✓ Success: Installation completes without errors

3

Create Mode Switch Configuration

🕒 Time: 1 minute

Why: This configuration file tells the modem to switch from WiFi hotspot to USB network mode.

sudo tee /etc/usb_modeswitch.d/12d1:14db << 'EOF' # Qualcomm 8916 - Switch to RNDIS mode DefaultVendor=0x12d1 DefaultProduct=0x14db MessageContent="55534243123456702000000080000c85010101180101010101000000000000" NoDriverLoading=1 EOF

✓ Success: File created at /etc/usb_modeswitch.d/12d1:14db

4

Create Auto-Switch Rule

🕒 Time: 1 minute

Why: This makes the mode switch happen automatically whenever you plug in the modem.

sudo tee /etc/udev/rules.d/70-qmi-to-rndis.rules << 'EOF' SUBSYSTEM=="usb", ATTRS{idVendor}=="12d1", ATTRS{idProduct}=="14db", RUN+="/usr/sbin/usb_modeswitch -v 12d1 -p 14db -c /etc/usb_modeswitch.d/12d1:14db" EOF

✓ Success: Rule file created successfully

5

Apply Changes & Reconnect

🕒 Time: 2 minutes

Why: We need to reload the system rules and physically reconnect the modem to trigger the mode switch.

First, reload the rules:

sudo udevadm control --reload-rules sudo systemctl restart ModemManager

Then reconnect the modem:

  1. Unplug the USB modem
  2. Wait 5 seconds
  3. Plug it back in
  4. Wait 30 seconds for mode switch

✓ Success: Modem reconnected and mode switched

6

Configure Network

🕒 Time: 1 minute

Why: The modem is now in USB network mode, but we need to request an IP address to connect to the internet.

sudo dhclient usb0

This command may take 10-20 seconds to complete.

✓ Success: Command completes without errors

7

Verify Connection

🕒 Time: 1 minute

Why: Let's make sure everything is working correctly before moving on.

# Check interface exists ip addr show usb0 # Test internet connection ping -c 4 google.com

✓ Success: You see an IP address on usb0 and ping responds successfully

🎉 Setup Complete!

Your modem is now providing internet directly via USB connection.

🔧 Troubleshooting

Common Issues

❌ Modem not detected

  • Check LED is on (if off, try different USB port)
  • Wait full 60 seconds after plugging in
  • Try USB 2.0 port instead of 3.0
  • Check SIM card is inserted correctly
  • Verify with: lsusb | grep 12d1

❌ No internet after setup

  • Verify SIM has active data plan
  • Check if APN configuration is needed for your carrier
  • Try accessing modem web interface: 192.168.1.1
  • Check signal strength (should have at least 2 bars)

USB Mode Issues

❌ No usb0 interface after mode switch

  • Check modem vendor/product ID: lsusb | grep 12d1
  • Try manual switch: sudo usb_modeswitch -v 12d1 -p 14db -c /etc/usb_modeswitch.d/12d1:14db
  • Check kernel messages: dmesg | tail -50
  • Ensure ModemManager is not interfering: sudo systemctl stop ModemManager

❌ Interface exists but no internet

  • Run dhclient again: sudo dhclient -v usb0
  • Check routing: ip route
  • Restart networking: sudo systemctl restart networking

📋 Additional Information

Supported Networks:

4G LTE, 3G WCDMA, 2G GSM (auto-switching)

Default Credentials:

Web interface: admin/admin (check device label)

Power Consumption:

~2W average (500mA @ 5V)

LED Indicators:

  • Solid: Connected to network
  • Blinking: Searching for network
  • Off: No power or SIM issue

🚀 Next Steps

Now that your internet connection is set up, you can: