Skip to content

MODEM_ID_GUIDE.md

Latest commit

 

History

History
174 lines (120 loc) · 3.71 KB

MODEM_ID_GUIDE.md

File metadata and controls

174 lines (120 loc) · 3.71 KB

Modem ID Re-enumeration Guide

Supported Modems

  • SIM7600G-H: USB ID 1e0e:9001 (Qualcomm/Option)
  • SIM7080: USB ID 1e0e:9205 (Qualcomm/Option SimTech)

Problem: Modem Changes from 0 to 1 (or vice versa)

When ModemManager restarts or the USB connection resets, the modem may be re-enumerated with a different ID:

# Before restart
$ mmcli -L
/org/freedesktop/ModemManager1/Modem/0 [QUALCOMM INCORPORATED] SIMCOM_SIM7600G-H

# After restart
$ mmcli -L
/org/freedesktop/ModemManager1/Modem/1 [QUALCOMM INCORPORATED] SIMCOM_SIM7600G-H

Solution: Auto-Detection

All scripts now automatically detect the current modem ID:

Scripts with Auto-Detection

  1. connect-cellular-dynamic.sh - Automatically finds modem ID
  2. cellular-debug.sh - Automatically finds modem ID
  3. cellular-recover.sh - Automatically finds modem ID
  4. get-modem-id.sh - Returns current modem ID

Usage

Just run the scripts normally - they handle the ID detection:

# These work regardless of modem ID (0, 1, 2, etc.)
sudo /opt/cellular/connect-cellular-dynamic.sh
sudo /opt/cellular/cellular-debug.sh status
sudo /opt/cellular/cellular-recover.sh

Manual Modem ID Detection

If you need to know the current modem ID:

# Method 1: Using the helper script
./get-modem-id.sh

# Method 2: Using mmcli directly
mmcli -L | grep -oP 'Modem/\K[0-9]+'

# Method 3: List all modems
mmcli -L

Bearer ID Relationship

The bearer ID is automatically calculated as:

BEARER_ID = MODEM_ID + 1

So:

  • Modem 0 → Bearer 1
  • Modem 1 → Bearer 2
  • Modem 2 → Bearer 3

How Auto-Detection Works

The scripts use this pattern:

# Find the first (and usually only) modem
MODEM_ID=$(mmcli -L 2>/dev/null | grep -oP 'Modem/\K[0-9]+' | head -1)

# If not found, default to 0
if [[ -z "$MODEM_ID" ]]; then
    MODEM_ID=0
fi

# Calculate bearer ID
BEARER_ID=$((MODEM_ID + 1))

Troubleshooting

"No modem found" Error

If auto-detection fails:

# Check if ModemManager is running
sudo systemctl status ModemManager

# Restart ModemManager
sudo systemctl restart ModemManager
sleep 3

# Try again
mmcli -L

Multiple Modems

If you have multiple modems, the scripts will use the first one found. To use a specific modem:

# List all modems
mmcli -L

# Use specific modem (e.g., modem 2)
sudo mmcli -m 2

Old Hardcoded Approach (Not Recommended)

Before auto-detection, scripts had hardcoded modem IDs:

# Old way (doesn't work after re-enumeration)
MODEM_ID=0
BEARER_ID=1

# New way (works with any modem ID)
MODEM_ID=$(mmcli -L | grep -oP 'Modem/\K[0-9]+' | head -1)
BEARER_ID=$((MODEM_ID + 1))

When Modem ID Changes

Modem ID changes when:

  1. ModemManager restarts - System reboot, service restart
  2. USB connection resets - Unplugging/replugging USB cable
  3. Modem firmware update - Modem updates its firmware
  4. Multiple modems - Adding/removing other modems

The auto-detection handles all these cases automatically.

Verification

To verify auto-detection is working:

# Run the debug script
sudo /opt/cellular/cellular-debug.sh status

# It will show the detected modem ID in the output
# Example output:
# [INFO] Modem 0 details:
# [INFO] Modem 0 status:

Or check the connection script output:

sudo /opt/cellular/connect-cellular-dynamic.sh

# Output will show:
# [INFO] Step 1: Enabling modem 1...
# [INFO] Step 2: Creating bearer with APN=ereseller, IP-Type=ipv4v6...

Summary

✅ All scripts now auto-detect modem ID ✅ Works with any modem ID (0, 1, 2, etc.) ✅ No manual configuration needed ✅ Handles re-enumeration automatically

Just use the scripts normally - they handle the modem ID detection for you!