Protocol Anatomy Guide
Master the interactive byte-level explorer. Click, filter, deep dive, and export UDS protocol messages like a pro.
- The Byte Canvas
Every UDS message is visualized as a row of color-coded byte modules. Each module represents one or more bytes of the protocol frame.
The Service Identifier. Always byte 0 of every request frame.
Operation modifier (e.g., session type, reset mode).
Data identifiers, addresses, and payload bytes.
Timing values, format specifiers, and optional fields.
Try it: Click any byte module below to expand its details panel. Click again to collapse.
- View Modes
Toggle between three viewing modes using the control in the top-right corner:
- ⧉ Split — Side-by-side Request and Response (default)
- → TX — Request bytes only
- ← RX — Response bytes only
- Alternative Value Explorer
Some bytes have multiple valid values (alternatives). When you click a byte with a purple dot, the details panel shows all possible values.
Click an alternative to see the hex value morph live in the byte canvas. Click the original value or the ”↺ Reset to default” button to revert.
- Semantic Filter
The filter toolbar lets you highlight specific byte types. Click a filter chip to dim all non-matching bytes, making it easy to focus on just the SID, sub-functions, or data fields.
Click the same chip again to deactivate the filter and show all bytes.
- Deep Dive Modal
When a byte has enriched data (ISO references, usage notes, related services), the details panel shows a “Deep Dive ↗” button. Clicking it opens a full modal with three tabs:
- ISO Spec — The exact section reference from ISO 14229-1:2020, usage notes, and a metadata grid
- Code — Copy-paste code snippets in TypeScript, Python, and C for constructing this byte
- Related — Links to related UDS services and common usage patterns
Press Escape to close the modal, or click the backdrop.
- Live Example
Here’s a fully interactive Protocol Anatomy for SID 0x10 — Diagnostic Session Control. Try all the features described above:
◆ PROTOCOL ANATOMY
0x10 DIAGNOSTIC SESSION CONTROL
0x10 RESPONSE
- Keyboard Navigation
Full keyboard support is built in for accessibility:
| Key | Action |
|---|---|
| ← → | Move focus between bytes |
| Home / End | Jump to first / last byte |
| Enter / Space | Select / activate a byte |
| Escape | Close details panel or modal |
Next Steps
Now that you understand the Protocol Anatomy component, explore the full documentation for each UDS service: