Telon GSM-SIP Gateway

About

📱 The Telon GSM-SIP Gateway is an Android application that acts as a bidirectional bridge between GSM telephony and SIP (Session Initiation Protocol). It enables seamless integration of local GSM calls with SIP-based telephony systems, allowing users to make and receive calls through SIP infrastructure while using GSM hardware.

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How It Works

Core Architecture

The application consists of two main endpoints that work together to bridge GSM and SIP communications:

1. Telephony Endpoint (react-native-tele): Handles GSM/telephony operations
2. SIP Endpoint (react-native-sip2): Manages SIP protocol communications

Call Flow

Incoming SIP → Outgoing GSM

1. SIP call is received by the SIP endpoint
2. Application extracts the destination number from SIP call
3. Initiates outgoing GSM call using the telephony endpoint
4. Bridges audio between SIP and GSM calls
5. Handles call state synchronization (ringing, connected, terminated)

Incoming GSM → Outgoing SIP

1. GSM call is received by the telephony endpoint
2. Application automatically rejects incoming GSM calls (for security)
3. Only outgoing GSM calls initiated by SIP are processed

Device-Specific Configuration

The application automatically configures itself based on the device ID:

Device ID	SIP Account	GSM Configuration
sp7731cea	50015	ReplaceDialer: true, Permissions: true
Impress_City	50014	ReplaceDialer: false, Permissions: false
Impress_Tor	50017	ReplaceDialer: true, Permissions: true
QC_Reference_Phone	50019	ReplaceDialer: true, Permissions: true, fas: false
MSM8937	50018	ReplaceDialer: true, Permissions: true, fas: false
Default	50016	ReplaceDialer: false, Permissions: false

SIP Configuration

• Server: 192.168.88.254
• Transport: UDP
• Registration Timeout: 3600 seconds
• Network: Supports WiFi, 3G, Edge, GPRS, and roaming

Special Test Numbers

• 50014-50019: Test calls with fast answer
• 3333: Test call with destination "900"
• 4444: Test call with audio session activation

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Features

• 🔄 Bidirectional Gateway: Routes calls between GSM and SIP networks
• 📱 Device Auto-Configuration: Automatically detects and configures based on device ID
• 🔒 Security: Rejects incoming GSM calls to prevent unauthorized access
• 📊 Real-time Logging: Comprehensive logging for monitoring and debugging
• ⚙️ Magisk Integration: System-level permissions for telephony operations
• 🎵 Audio Bridging: Seamless audio routing between GSM and SIP calls

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Technical Requirements

Prerequisites

• 📱 Android device running version 8.0 (Oreo) or higher
• 🔧 Root access (for Magisk module installation)
• 📡 GSM SIM card with active service
• 🌐 Network connectivity for SIP registration

System Permissions

The application requires elevated permissions through Magisk:

• android.permission.READ_LOGS
• android.permission.CAPTURE_AUDIO_OUTPUT
• android.permission.READ_PRECISE_PHONE_STATE
• android.permission.MODIFY_PHONE_STATE

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Installation

Pre-installation Setup

Clone the required repositories to a common folder:

# Clone the main repository
git clone https://github.com/telon-org/telon-gsm-sip-gateway.git

# Clone the required libraries to the same directory level
git clone https://github.com/telon-org/react-native-tele.git
git clone https://github.com/telon-org/react-native-sip2.git
git clone https://github.com/telon-org/react-native-replace-dialer.git

Your directory structure should look like this:

common-folder/
├── telon-gsm-sip-gateway/
├── react-native-tele/
├── react-native-sip2/
└── react-native-replace-dialer/

Build and Installation

1. Install Magisk Module: Flash the magisk/gateway.zip module
2. Build Application: Use GitHub Actions or run yarn android
3. Install APK: Install the generated APK on your device

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Usage

Initial Setup

1. 🚀 Launch the Telon GSM-SIP Gateway app
2. 📱 Grant necessary permissions when prompted
3. 🔧 The app will automatically configure based on your device ID
4. 📊 Monitor the gateway log for connection status

Operation

• The application runs in the background
• SIP calls are automatically routed to GSM
• All call states are synchronized between networks
• Real-time logs show call progress and any issues

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Troubleshooting

Common Issues

• SIP Registration Failed: Check network connectivity and server configuration
• Audio Issues: Verify device audio permissions and hardware compatibility
• Call Routing Problems: Check device ID configuration and SIP account settings

Debug Information

• View real-time logs in the application console
• Check Magisk module installation status
• Verify system permissions are properly granted

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Development

Dependencies

• react-native-tele: GSM/telephony operations
• react-native-sip2: SIP protocol handling
• react-native-replace-dialer: Default dialer replacement
• react-native-device-info: Device identification

Building from Source

cd telon-gateway-app
yarn install
yarn android

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Contributing

🤝 We welcome contributions! Here's how you can help:

1. 🍴 Fork the repository
2. 🌱 Create a feature branch: git checkout -b feature-name
3. 💾 Commit your changes: git commit -m "Add feature description"
4. 🔼 Push the branch: git push origin feature-name
5. 📝 Create a pull request

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License

📜 This project is licensed under the ISC License.

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Support

💌 For support or inquiries, please visit telon.org or contact us at [email protected].

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Acknowledgments

🙏 Special thanks to the contributors and the open-source community for making this project possible.