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Documentation Index

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Tachoparser decodes tachograph data into two top-level Go structs: Card for driver card files and Vu for vehicle unit files. Both are serialised to JSON by the dddparser tool. This page documents the major fields exposed in that JSON output, grouped by section. Each data block also carries a verified boolean that reflects whether its cryptographic signature passed validation.

​
The verified field

Every data block that carries a signature — overview blocks, activity arrays, events, faults, technical data — has a verified field in the JSON output. It is set to true only when all of the following conditions are met:
  1. The relevant public keys were loaded at startup (via internal/pkg/certificates).
  2. The certificate chain embedded in the file (ERCA root → member state → VU/card) decoded successfully.
  3. The block’s signature verified against its certificate and the block’s raw bytes.
If any condition fails, verified remains false. Parsing itself still succeeds — only the verified field is affected.

​
Card data (-card)

Driver card files use TLV encoding. The Card struct holds every TLV-encoded section. Fields for the same logical section come in pairs: a _1 variant for 1st-generation data and a _2 variant for 2nd-generation data. Both variants may be present in the same file.
Identifies the integrated circuit chip on the card. Present as card_icc_identification_1 (TLV tag 0x000200) for 1st-generation data and card_icc_identification_2 (tag 0x000202) for 2nd-generation data.
{
  "card_icc_identification_1": {
    "verified": true,
    "clock_stop": 0,
    "card_extended_serial_number": { ... },
    "card_approval_number": "...",
    "card_personaliser_id": 0,
    "embedder_ic_assembler_id": "...",
    "ic_identifier": "..."
  }
}
Contains the chip’s unique serial number and related identification bytes. Available as card_chip_identification_1 (tag 0x000500) and card_chip_identification_2 (tag 0x000502).
{
  "card_chip_identification_1": {
    "verified": true,
    "ic_serial_number": "...",
    "ic_manufacturing_references": "..."
  }
}
Records the tachograph application type, version, and capacity parameters (for example, the maximum number of activity records the card can store). Available as driver_card_application_identification_1 (tag 0x050100) and driver_card_application_identification_2 (tag 0x050102). A v2-specific variant is also present as driver_card_application_identification_v2 (tag 0x052502).
{
  "driver_card_application_identification_1": {
    "verified": true,
    "type_of_tachograph_card_id": 1,
    "card_structure_version": "...",
    "no_of_events_per_type": 6,
    "no_of_faults_per_type": 12,
    "activity_structure_length": 5548,
    "no_of_card_vehicle_records": 84,
    "no_of_card_place_records": 84
  }
}
Lists driving events such as power supply interruptions, motion sensor errors, over-speeding, and continuous driving violations. Available as card_event_data_1 (tag 0x050200) and card_event_data_2 (tag 0x050202).
{
  "card_event_data_1": {
    "verified": true,
    "card_event_records": [
      {
        "event_type": 1,
        "event_begin_time": "2023-04-01T07:12:00Z",
        "event_end_time": "2023-04-01T07:14:00Z",
        "similar_events_number": 0
      }
    ]
  }
}
Records equipment faults detected by the tachograph. Available as card_fault_data_1 (tag 0x050300) and card_fault_data_2 (tag 0x050302).
{
  "card_fault_data_1": {
    "verified": true,
    "card_fault_records": [
      {
        "fault_type": 64,
        "fault_begin_time": "2023-01-15T09:00:00Z",
        "fault_end_time": "2023-01-15T09:05:00Z"
      }
    ]
  }
}
Contains the driver’s raw activity byte stream, which encodes the sequence of activity changes (driving, work, availability, rest) with minute-resolution timestamps. Available as card_driver_activity_1 (tag 0x050400) and card_driver_activity_2 (tag 0x050402).
{
  "card_driver_activity_1": {
    "verified": true,
    "activity_pointer_oldest_day_record": 0,
    "activity_pointer_newest_record": 2784,
    "activity_daily_records": [
      {
        "activity_previous_record_length": 0,
        "activity_record_length": 56,
        "activity_record_date": "2023-04-01",
        "activity_daily_presence_counter": 1,
        "activity_distance": 342,
        "activity_change_infos": [ ... ]
      }
    ]
  }
}
Lists the vehicles the driver operated, including VIN, registration number, odometer readings, and the time period the card was inserted. Available as card_vehicles_used_1 (tag 0x050500) and card_vehicles_used_2 (tag 0x050502).
{
  "card_vehicles_used_1": {
    "verified": true,
    "vehicle_pointer_newest_record": 3,
    "card_vehicle_records": [
      {
        "vehicle_odometer_begin": 123456,
        "vehicle_odometer_end": 124100,
        "vehicle_first_use": "2023-04-01T06:00:00Z",
        "vehicle_last_use": "2023-04-01T18:30:00Z",
        "vehicle_registration": { ... }
      }
    ]
  }
}
Records the geographic location at the start and end of each daily work period, as entered by the driver. Available as card_place_daily_work_period_1 (tag 0x050600) and card_place_daily_work_period_2 (tag 0x050602).
{
  "card_place_daily_work_period_1": {
    "verified": true,
    "place_pointer_newest_record": 5,
    "card_place_daily_work_period_records": [
      {
        "place_pointer_type_of_entry": 1,
        "entry_time": "2023-04-01T06:00:00Z",
        "entry_type_daily_work_period": 0,
        "entry_nation": 22,
        "entry_region": 0
      }
    ]
  }
}
Contains the card number, issuing member state, card validity dates, and the driver’s name and birth date. This is the primary identification section. Available as card_identification_and_driver_card_holder_identification_1 (tag 0x052000) and card_identification_and_driver_card_holder_identification_2 (tag 0x052002).
{
  "card_identification_and_driver_card_holder_identification_1": {
    "verified": true,
    "card_identification": {
      "card_issuing_member_state": 22,
      "card_number": "DE000123456789",
      "card_issuing_authority_name": "...",
      "card_issue_date": "2020-01-15",
      "card_validity_begin": "2020-01-15",
      "card_expiry_date": "2025-01-14"
    },
    "driver_card_holder_identification": {
      "card_holder_name": {
        "holder_surname": "Mustermann",
        "holder_first_names": "Max"
      },
      "card_holder_birth_date": "1980-06-12"
    }
  }
}

​
VU data (-vu)

Vehicle unit files use TV encoding. The Vu struct holds one overview block per generation (at most) and multiple activity, events, faults, detailed speed, and technical data blocks. Multiple blocks of the same type are common in real data.
The first-generation overview block (TV tag 0x7601) is the anchor for all 1st-gen signature verification. It embeds the MemberStateCertificate and VuCertificate at fixed offsets at the start of the block, followed by vehicle identification, downloadable period, card slot status, download activity data, company locks, and control activity data.
{
  "vu_overview_1": {
    "verified": true,
    "member_state_certificate": { ... },
    "vu_certificate": { ... },
    "vehicle_identification_number": { "vehicle_identification_number": "WBA12345678901234" },
    "vehicle_registration_identification": { ... },
    "current_date_time": "2023-04-01T18:30:00Z",
    "vu_downloadable_period": { "min_downloadable_time": "...", "max_downloadable_time": "..." },
    "card_slots_status": { ... },
    "vu_download_activity_data": { ... },
    "vu_company_locks_data": { ... },
    "vu_control_activity_data": { ... }
  }
}
The second-generation overview (TV tag 0x7621) and its v2 variant (TV tag 0x7631) serve the same anchoring role for 2nd-gen signature verification. Certificates are stored in record arrays (MemberStateCertificateRecordArray, VuCertificateRecordArray) rather than at fixed offsets.
{
  "vu_overview_2": {
    "verified": true,
    "member_state_certificate_record_array": { "records": [ { ... } ] },
    "vu_certificate_record_array": { "records": [ { ... } ] },
    "vu_identification_record_array": { ... },
    "vu_downloadable_period_record_array": { ... },
    "vu_card_iw_record_array": { ... },
    "vu_company_locks_record_array": { ... },
    "vu_control_activity_record_array": { ... },
    "sensor_paired_record_array": { ... }
  }
}
An array of 1st-gen daily activity blocks (TV tag 0x7602). Each element covers one calendar day and contains the driver slot, co-driver slot, and the raw activity change byte stream.
{
  "vu_activities_1": [
    {
      "verified": true,
      "time_real": "2023-04-01T00:00:00Z",
      "odometer_value_midnight": 123456,
      "vu_card_iw_data": { ... },
      "vu_activity_daily_data": "...",
      "vu_distance": { ... }
    }
  ]
}
An array of 2nd-gen daily activity blocks (TV tag 0x7622). The structure uses record arrays for driver, co-driver, and vehicle periods rather than the fixed-layout approach of the 1st generation.
{
  "vu_activities_2": [
    {
      "verified": true,
      "vu_gnss_ad_record_array": { ... },
      "vu_activity_daily_record_array": { ... },
      "vu_place_daily_work_period_record_array": { ... },
      "vu_gnss_place_auth_record_array": { ... }
    }
  ]
}
An array of 2nd-gen v2 daily activity blocks (TV tag 0x7632). Extends the 2nd-gen structure with GPS-authenticated accumulated driving records, border crossing records, and load/unload records.
{
  "vu_activities_2_v2": [
    {
      "verified": true,
      "vu_gnss_ad_record_array": { ... },
      "vu_activity_daily_record_array": { ... },
      "vu_place_daily_work_period_record_array": { ... },
      "vu_gnss_place_auth_record_array": { ... },
      "vu_border_crossing_record_array": { ... },
      "vu_load_unload_record_array": { ... }
    }
  ]
}

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