Derive structure
- Separate requests, responses and unsolicited messages.
- Test delimiters, fixed sizes, length fields and time-gap boundaries.
- Correlate commands through echoed IDs, addresses or counters.
- Compare payload values as little- and big-endian integers, BCD, floating point or encoded text.
- Identify escaping before interpreting delimiter-like bytes.
- Test checksum/CRC candidates across a large independent sample.
Recover state, not just fields
| Same request, different response | Device mode, initialization or prior command matters. |
|---|---|
| Counter changes every frame | Sequence correlation, replay protection or sample index. |
| Length/checksum fails after byte removal | Escaping or transport logging may have transformed data. |
| Silence after valid-looking frame | Wrong state, timing, address or safety interlock. |
Validate safely
Change one known input at a time, predict the frame before capture and validate against unseen exchanges. Do not replay write/motion commands without understanding consequences.
Acquire evidence through traffic capture, detect settings with baud-rate analysis and place results in the broader device model. Replacement clients belong in RS232 development.
Provide raw directional captures, annotations, device states and required operations.