SIM800L SMS Manager

A secure SMS management application for SIM800L GSM modules with full Unicode and emoji support.

Features

• Send and receive SMS messages in real-time
• Multi-language support (English, Arabic, Persian, Chinese, emoji)
• Modern chat-style user interface
• Contact management system
• Automatic encoding detection (7-bit GSM / UCS2)
• PDU mode for Unicode messages
• Desktop notifications
• Thread-safe operations
• Secure input validation

Requirements

• Java 17 or higher
• Maven 3.6+ (for building)
• SIM800L GSM module
• USB-to-Serial adapter
• Active SIM card

Installation

Option 1: Download Release (Recommended)

Download pre-built executables from Releases:

• Linux: SIM800L-Manager-linux-x64.tar.gz
• Windows: SIM800L-Manager-windows-x64.zip
• macOS: SIM800L-Manager-macos-x64.dmg

No Java installation required!

Option 2: Build from Source

git clone https://github.com/yourusername/sim800l-manager.git
cd sim800l-manager
mvn clean package

Run Application

mvn javafx:run

Or run the compiled JAR:

java -jar target/SIM800LManager-v2.0.jar

Quick Start

1. Connect SIM800L module via USB-Serial adapter
2. Insert active SIM card and power on
3. On Linux, add user to dialout group:

   sudo usermod -aG dialout $USER

4. Launch application and select serial port
5. Click "Connect" and wait for confirmation
6. Start sending messages

Usage

Sending Messages

Text Mode (English) - Up to 160 characters:

Hello, how are you?

PDU Mode (Unicode) - Up to 70 characters:

مرحبا كيف حالك？
你好，这是一条测试消息。
Hello 😀 How are you? 🎉

The application automatically detects the appropriate encoding mode.

Message Encoding

Type	Encoding	Max Length
English/ASCII	7-bit GSM	160 chars
Unicode/Emoji	UCS2	70 chars

Configuration

Data Storage

Application data is stored in ~/.sim800l/:

• chats.dat - Message history
• contacts.dat - Saved contacts

Serial Port Settings

• Baud Rate: 9600
• Data Bits: 8
• Stop Bits: 1
• Parity: None

Security

This application implements comprehensive security measures:

• Input validation and sanitization
• Command injection prevention
• ReDoS protection
• Safe deserialization
• Thread-safe operations

For details, see SECURITY.md.

Troubleshooting

Connection Issues

Cannot connect to serial port:

1. Check SIM800L power LED is blinking
2. Verify USB cable connection
3. Check serial port permissions (Linux)
4. Try different serial ports

Module not responding:

1. Verify power supply (4.2V, 2A required)
2. Check SIM card insertion
3. Wait 10-15 seconds after power on
4. Restart the module

Message Issues

Cannot send Unicode:

• Automatic PDU encoding is enabled
• Check SIM card supports Unicode SMS

Message too long:

• English/ASCII: max 160 characters
• Unicode: max 70 characters
• Emoji counted correctly (no concatenation support)

Building

# Compile
mvn clean compile

# Build JAR
mvn clean package

# Run
mvn javafx:run

Output: target/SIM800LManager-v2.0.jar

Project Structure

src/main/java/com/sim800l/
├── SIM800LApp.java              # Main application
├── SerialPortManager.java       # Serial communication
├── PDUEncoder.java              # PDU encoding
├── MessageEncoder.java          # Text encoding
├── DataManager.java             # Data persistence
├── Contact.java                 # Contact model
├── ChatMessage.java             # Message model
├── NotificationManager.java     # Notifications
└── Theme.java                   # UI theming

Dependencies

• JavaFX 17.0.2 - UI framework
• jSerialComm 2.10.4 - Serial communication

Contributing

Contributions are welcome. Please:

1. Fork the repository
2. Create a feature branch
3. Make your changes
4. Test thoroughly
5. Submit a pull request

License

MIT License - see LICENSE file for details.

Support

• Issues: GitHub Issues
• Security: SECURITY.md

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Made with care for reliable SMS communication.