JT/T 808-2023 Binary Frame Visualizer

A modern, single‑page web tool to decode and inspect raw JT/T 808 (2019/2023‑compatible) GPS tracking frames.
Paste a hex string, hit Parse frame, and instantly explore header fields, location data, alarms, status bits, and additional information in a rich UI.

Built as a browser‑only tool – no backend, no build system.

• Hex → Structured decode

  • Accepts hex with or without 7E frame delimiters.
  • Ignores spaces and line breaks.
  • Validates the XOR checksum.

• Protocol‑aware parsing

  • Escape/unescape handling (7D 02 → 7E, 7D 01 → 7D).
  • Message header decoding:
    • Message ID and friendly name.
    • Body properties (length, encryption flags, fragmentation).
    • Terminal phone number (BCD).
    • Message serial number.
    • Fragmented message info (total packets, packet index).

• Supported message types

  • 0x0002 – Terminal Heartbeat (no body).
  • 0x0100 – Terminal Registration.
  • 0x0102 – Terminal Authentication.
  • 0x0107 – Query Terminal Attribute Response (basic).
  • 0x0200 – Location Information Report.
  • 0x0704 – Positioning Data Bulk Upload (batch of 0x0200).
  • 0x8001 – Platform Universal Response.
  • 0x8100 – Terminal Registration Response.

• 0x0200 location details

  • Alarm flags (32 bits).
  • Status flags (ACC, GNSS constellations, doors, etc.).
  • Latitude / longitude (scaled, degrees).
  • Altitude, speed, direction.
  • BCD time decoding.
  • Additional information items (0x30, 0x31, 0x51, 0x56, 0x57, 0x63, 0xFD, …).

• 0x0704 bulk upload

  • Item count and location type (normal / blind area).
  • Each embedded 0x0200 parsed and shown in its own expandable panel.

• Polished UI

  • Dark, dashboard‑style layout.
  • Success/error alerts with meaningful messages.
  • Header summary panel with pills and badges.
  • Collapsible sections for bulk uploads.
  • Hex dump for both body and normalized original frame.

git clone https://github.com/rootcastleco/jt808-parser.git
cd jt808-parser

You can simply open index.html directly, or serve it via a tiny static server:

# Python 3
python -m http.server 8080

# then open:
# http://localhost:8080/index.html

No build step, dependencies, or backend services are required.

1. Open the HTML page in your browser.
2. Paste a JT/T 808 frame as a hex string into the Hex String textarea.
   • You may include or omit starting/ending 7E.
   • Whitespace is ignored.
3. Click Parse frame.
4. Inspect the decoded result:
   • Header (MsgID, phone, serial number, body length, encryption, fragmentation, checksum).
   • Message‑type specific sections (location, registration, responses…).
   • Raw body hex and normalized frame hex.

You can also use the built‑in demo buttons:

• Load 0x0200 example – inserts a sample Location Information Report and parses it.
• Load 0x0704 example – inserts a bulk upload frame and parses all embedded locations.
• Clear – resets input and output.

This project is intentionally minimal:

.
└── index.html   # Contains HTML, CSS and JavaScript for the entire tool

All parsing logic, visualization components, and styling live in index.html, so you can drop it into any environment that can serve static files.

• Remove non‑hex characters.
• Optionally strip leading and trailing 7E.
• Convert pairs of hex characters to bytes.
• Unescape:
  • 0x7D 0x02 → 0x7E
  • 0x7D 0x01 → 0x7D

• XOR of all bytes from the start of the header up to the last body byte.
• Compared against the last byte of the unescaped frame.
• Any mismatch is reported as a human‑readable error.

• msgId – 2 bytes, big‑endian.
• bodyProps – 2 bytes, split into:
  • lower 10 bits: body length.
  • bits 10–12: encryption type.
  • bit 13: fragmentation flag.
• Phone number – 6 bytes BCD → string.
• serialNumber – 2 bytes.
• If fragmented:
  • totalPackets – 2 bytes.
  • packetIndex – 2 bytes.

• 0x0200: reads fixed header fields, then loops through additional information TLV items.
• 0x0704: reads count and type, then repeatedly reads length‑prefixed embedded 0x0200 payloads.
• 0x0100 / 0x8100 / 0x0102 / 0x8001: extract fields according to the protocol and display them in the UI.

You can easily extend or adapt the parser:

• Add new message IDs and names to the MSG_NAMES map.
• Implement additional parsers and hook them into the switch (frame.msgId) block.
• Extend ADDITIONAL_INFO_IDS to cover more custom or vendor‑specific items.
• Adjust the UI to match your branding or integrate into your own debug tools.

• Export parsed data as JSON.
• Import/export frames from text files.
• Add more message types (e.g., media, events, driver info).
• Add unit tests for parsing functions.
• Optional multi‑language UI (English, Chinese, Turkish).