FPV 아날로그 비디오 스크램블러 모듈 암호화 시드 수정

Modify FPV Analog Video Scrambler Module Encryption Seed

A recent customer integration project focused on our FPV Analog Video Scrambler & Descrambler Module, configured via the CVBS 스크램블링 도우미, raised several detailed technical questions. The customer aims to modify and synchronize the encryption seed (scramble sequence) from their own embedded controller, without using a PC or the standard assistant software.

We are integrating your FPV Analog Video Scrambler & Descrambler Module (the one configured via the “CVBS Scrambling Assistant”) into our own system and need to clarify some technical details about the configuration interface.

From the description on your website, we can see that:

1. the module is configured via USB–Serial (CH340);
2. your software has Read / Write commands to read the device parameters and to write values (scramble/descramble sequence).

다음 사항을 확인해 주세요.:

1. Does the module in fact have a UART (TTL) interface through which your software exchanges commands with the module?
2. What are the exact UART parameters (전송 속도, 데이터 비트, 둥가, 정지 비트)?
3. Is the communication protocol open? We need to send the same commands that your software sends, but not from a PC — from our own external device (controller/programmer).
4. What is the packet structure for writing the seed:
   service/header byte(에스),
   command byte,
   data length,
   field with the seed / scramble sequence itself,
   checksum type (CRC, XOR or other).
5. Is it possible to write the seed in working mode (when the module is already connected to video), or can this only be done in configuration mode?
6. Is the write command the same for the module in Scrambler mode and in Descrambler mode, or is there a different command for the RX unit?
   What is the maximum seed/sequence length and what format is allowed (digits only, hex, ASCII)?
7. If the protocol is currently not public, could you send us a short PDF/text description of the commands or an example of the log of your PC software communicating with the module (so that we can reproduce it in our device)?

Our task is to write/update the encryption key (seed) without using a PC, only from our device via UART, so that we can set the same seed on both the transmitting and the receiving modules at the same time.

We would appreciate it if you could provide:
the command description;
an example of a “write seed” packet;

Their main goal is to automate the seed writing process over UART, setting the same encryption key for both transmitting (TX) and receiving (RX) modules simultaneously.

The inquiry covered the following technical topics:

1. UART Communication Interface – Whether the module features a TTL-level UART interface communicating through a USB–Serial (CH340) 변환기.
2. UART Parameters – Required serial settings such as baud rate, 데이터 비트, 둥가, and stop bits.
3. Open Protocol Access – Whether it is possible to send read/write commands directly from an external microcontroller instead of the PC software.
4. Packet Format for Write Seed Command – Header bytes, command type, data length, seed field, and checksum (CRC or XOR).
5. Configuration vs. 작업 모드 – Whether the seed can be updated while video is being transmitted.
6. TX/RX Synchronization – Whether Scrambler and Descrambler share the same write-seed command and allowed seed format (numeric, ASCII, hex).
7. Protocol Documentation – Request for a short command reference or communication log for replication purposes.

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Technical Explanation and Integration Guide

The FPV Analog Video Scrambler & Descrambler module features an internal UART configuration interface accessible via a USB–Serial (CH340) 다리. The same communication channel used by the PC assistant software can also be accessed by an external embedded system for advanced integration.

Typical UART parameters:

• 전송 속도: 115200 bps
• Data bits: 8
• 동등: 없음
• 정지 비트: 1

The configuration protocol is binary and optimized for writing and reading encryption parameters. While the complete command protocol is not publicly distributed, authorized integrators may obtain a command summary or example communication log under an NDA.

Regarding operation modes:

• 구성 모드 – The recommended mode for writing or updating the encryption seed before video transmission begins.
• 작업 모드 – In some firmware versions, it is possible to modify the seed in real time, depending on the synchronization method between TX and RX.

Both the Scrambler (TX) and Descrambler (RX) share the same write-seed command format, ensuring consistent decryption across paired modules. The seed supports up to 16 캐릭터, typically in ASCII or numeric format depending on firmware configuration.

For developers who wish to control the module via an MCU, 사용하여 UART logic analyzer to record the command sequence from the CVBS Scrambling Assistant software provides a practical path to replicate the same protocol in their own system.

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실제 응용 프로그램

This feature is widely used in UAV analog video transmission, 무선 감시, 과 secure tactical communication systems, where synchronized encryption between transmitter and receiver is critical.

By allowing UART-based control of the encryption key, system designers can easily integrate scrambling logic into custom controllers, achieving full automation and seamless synchronization across the video link.

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