fix(protocol): correct continuous-mode record header classification for accurate timestamp extraction

CHANGELOG.md

@@ -4,6 +4,27 @@ All notable changes to seismo-relay are documented here.
 
 ---
 
+## v0.13.1 — 2026-05-01
+
+### Fixed
+
+- **`_extract_record_type` — Continuous-mode record headers misclassified as Unknown.**
+  In single-shot mode the 0C waveform record's 9-byte header puts the sub_code
+  marker `0x10` at byte 1, with the day at byte 0.  In Continuous mode the
+  header is 10 bytes with the marker at byte 0 *and* byte 2, and the day at
+  byte 1.  Previous logic only inspected byte 1 and treated any value other
+  than `0x10` / `0x03` as `"Unknown"`, which prevented `event.timestamp` from
+  being populated for any continuous-mode event whose day-of-month wasn't
+  exactly 3 or 16.  As a downstream effect, `blastware_filename()` saw
+  `event.timestamp == None`, fell back to `stem="0000"` / `ab="00"`, and
+  produced filenames like `M5290000.000`.  Discovered from a live SFM run on
+  BE11529 in continuous mode (day-of-month = 5).
+  Now disambiguates by checking BOTH byte 0 and byte 2: if both are `0x10`,
+  it's the 10-byte continuous header; else if byte 1 is `0x10`, it's the
+  9-byte single-shot header.  Day-of-month no longer matters.
+
+---
+
 ## v0.13.0 — 2026-05-01
 
 ### Fixed

CLAUDE.md

@@ -2,7 +2,7 @@
 
 Ground-up Python replacement for **Blastware**, Instantel's Windows-only software for
 managing MiniMate Plus seismographs. Connects over direct RS-232 or cellular modem
-(Sierra Wireless RV50 / RV55). Current version: **v0.13.0**.
+(Sierra Wireless RV50 / RV55). Current version: **v0.13.1**.
 
 When new information about the protocol is discovered, please update the instantel_protocol_reference.md with the findings in addition to this document
 

minimateplus/client.py

@@ -1638,31 +1638,48 @@ def _decode_a5_waveform(
 
 def _extract_record_type(data: bytes) -> Optional[str]:
     """
-    Decode the recording mode from byte[1] of the 210-byte waveform record.
+    Detect the waveform record format by inspecting the first 3 bytes of the
+    210-byte record returned by SUB 0C.
 
-    Byte[1] is the sub-record code that immediately follows the day byte in the
-    9-byte timestamp header at the start of each waveform record:
-      [day:1] [sub_code:1] [month:1] [year:2 BE] ...
+    Two formats exist (confirmed from BE11529 captures and CLAUDE.md docs):
 
-    Confirmed codes (✅ 2026-04-01):
-      0x10 → "Waveform"   (continuous / single-shot mode)
+      Single-shot mode — 9-byte header:
+        data[0]   = day
+        data[1]   = 0x10            ← sub_code marker
+        data[2]   = month
+        data[3:5] = year (BE)
+        ...
 
-    Histogram mode code is not yet confirmed — a histogram event must be
-    captured with debug=true to identify it.  Returns None for unknown codes.
+      Continuous mode — 10-byte header:
+        data[0]   = 0x10            ← marker A
+        data[1]   = day             ← variable (NOT 0x10)
+        data[2]   = 0x10            ← marker B
+        data[3]   = month
+        data[4:6] = year (BE)
+        ...
+
+    Disambiguate by checking BOTH data[0] and data[2]:
+      - data[0]==0x10 AND data[2]==0x10  →  Continuous (10-byte header)
+      - data[1]==0x10                    →  Single-shot (9-byte header)
+      - otherwise                        →  Unknown
+
+    Previous logic only checked data[1] and so mis-classified continuous-mode
+    records as "Unknown(0xXX)" wherever day != 0x10 — see filename
+    M5290000.000 regression report (2026-05-01 SFM log).
     """
-    if len(data) < 2:
+    if len(data) < 3:
         return None
-    code = data[1]
-    if code == 0x10:
-        return "Waveform"
-    if code == 0x03:
-        # Continuous mode waveform record (confirmed by user — NOT a monitor log).
-        # The byte layout differs from 0x10 single-shot records: the timestamp
-        # fields decode as garbage under the 0x10 waveform layout.
-        # TODO: confirm correct timestamp layout for 0x03 records from a known-time event.
+    # 10-byte continuous format: 0x10 markers at byte 0 AND byte 2
+    if data[0] == 0x10 and data[2] == 0x10:
         return "Waveform (Continuous)"
-    log.warning("_extract_record_type: unknown sub_code=0x%02X", code)
-    return f"Unknown(0x{code:02X})"
+    # 9-byte single-shot format: 0x10 sub_code marker at byte 1
+    if data[1] == 0x10:
+        return "Waveform"
+    log.warning(
+        "_extract_record_type: unrecognized header: data[0:3]=%02X %02X %02X",
+        data[0], data[1], data[2],
+    )
+    return f"Unknown({data[0]:02X}.{data[1]:02X}.{data[2]:02X})"
 
 
 def _extract_peak_floats(data: bytes) -> Optional[PeakValues]: