RT4D Codeplug Editor: A Modern, Open-Source Tool for Your RT-4D/Retevis RT84 Radio

Source code at https://github.com/jcalado/rt4d-cps

What is RT4D Codeplug Editor?

If you own a Radtel RT-4D (analog/DMR) radio, you know that programming it with the official Chinese Programming Software (CPS) can be… challenging. That’s where RT4D Codeplug Editor comes in - a modern, open-source alternative built from the ground up to make radio programming straightforward and reliable.

Why Use RT4D Editor?

🎯 Built for Accuracy

Unlike guesswork-based editors, RT4D Editor was developed through careful reverse-engineering of the official CPS. Every setting, every byte offset, every dropdown value has been verified against the official software to ensure your radio configuration is exactly what you expect.

🖥️ Clean, Modern Interface

Tabbed interface for organized access to Channels, Contacts, Zones, and Settings
Real-time editing with immediate visual feedback
Advanced settings dialog for power users who want full control
Cross-platform support - works on Windows, Linux, and macOS

📡 Complete Feature Support

Channel Management:

Supports all 1024 channels
Both analog (FM/AM/SSB) and DMR digital modes
Full CTCSS/DCS sub-tone support (all 210+ codes)
Scrambler, encryption, and privacy features
Talkaround, scan, and alarm settings

Contact & Zone Organization:

Manage up to 1000 DMR contacts
Group lists for organized contact groups
Zone-based channel organization
All Call, Group Call, and Private Call support

Radio Settings:

Identity: Radio name, DMR ID, startup messages
Audio: Separate controls for analog and DMR audio
- TX Mic Gain (0-31) and RX Speaker Volume (0-63)
- DMR Call audio with independent gain controls (0-24)
- Beep settings for various events
Display: LCD contrast, brightness, display modes
Power management and dual-watch settings
4 programmable clock/timers
Frequency lock ranges for band limiting
Scan settings (direction, dwell time, modes)
Function key programming (40 different actions)
DMR enhancements: hang times, remote control, call display
Advanced: NOAA weather channels, spectrum scan, detection range

How It Works

The editor reads and writes .4rdmf files - the binary codeplug format used by the RT-4D radio. The file structure includes:

CFG Section (4096 bytes): Radio settings, identity, audio, display
Channels (1024 × 48 bytes): All channel data
Contacts (1000 × 32 bytes): DMR contact directory
Group Lists (250 × 288 bytes): Contact groupings
Zones (250 × 512 bytes): Channel organization
Encryption Keys (256 × 40 bytes): Privacy keys

Every field has been mapped to its exact byte offset through careful analysis of the official CPS software, ensuring 100% compatibility with your radio.

Technical Details

For the technically curious:

Built With:

Python 3.x
PySide6 (Qt6) for the GUI
Binary parsing with struct module
GBK text encoding for Chinese character support
BCD encoding for DMR IDs

Key Architecture:

models.py - Data structures for all codeplug entities
parser.py - Binary file reading and conversion to Python objects
serializer.py - Python objects back to binary format
dropdowns.py - All valid values for radio settings
gui/ - Qt-based user interface

File Format Documentation: Complete documentation of the .4rdmf binary format is included in CODEPLUG_FORMAT.md, making it easy for other developers to build compatible tools.

Getting Started

Read from Radio: Use the official CPS to read your current config and save as .4rdmf
Open in RT4D Editor: Load the file and make your changes
Save: Export back to .4rdmf format
Write to Radio: Use the official CPS to write the modified file back

Settings Organization

The Advanced Settings dialog logically groups related settings:

📻 Analog Audio Settings - Squelch, mic gain, speaker volume, beeps for FM/AM/SSB operation
🔊 DMR Audio Settings - Separate controls optimized for digital voice with call-specific audio levels
🖥️ Display Settings - Screen brightness, contrast, display modes
📡 DMR Operation Settings - Remote control, hang times, call display
⚙️ Advanced Features - NOAA, spectrum scan, detection settings

Open Source & Community Driven

RT4D Codeplug Editor is open-source software, developed through reverse-engineering the official CPS to provide accurate, reliable radio programming. The project welcomes contributions, bug reports, and feature requests.

Key Benefits of Open Source:

Transparent code - see exactly what’s happening with your radio data
Community improvements - bugs get fixed quickly
Cross-platform - not locked to Windows
Future-proof - won’t become abandonware

What’s Next?

Future enhancements on the roadmap:

DTMF programming system UI (data structure complete)
Import/export from CSV for bulk editing

Conclusion

Whether you’re a ham radio operator, professional radio user, or just someone who wants reliable control over your RT-4D radio programming, RT4D Codeplug Editor offers a modern, accurate, and user-friendly alternative to the official CPS.

Github repo at https://github.com/jcalado/rt4d-cps

RT4D Codeplug Editor is not affiliated with or endorsed by the radio manufacturer. It’s an independent, community-driven project created through reverse-engineering for compatibility and educational purposes.

# RT4D Codeplug Editor - A Modern, Open-Source Tool for Your Radtel RT-4D Radio