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https://github.com/smittix/intercept.git
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645b3b8632
Stricter dot pattern detection (200 bits/100 alternations), bounded phasing strip (max 7), symbol check bit parity validation, EOS minimum position check, strict MMSI decode (reject out-of-range symbols), format-aware telecommand extraction, and expanded critical category detection. Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
474 lines
13 KiB
Python
474 lines
13 KiB
Python
"""
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DSC (Digital Selective Calling) constants per ITU-R M.493.
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This module contains all DSC-specific constants including format codes,
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distress nature codes, telecommand definitions, and MID (Maritime
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Identification Digits) country mappings.
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"""
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from __future__ import annotations
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# =============================================================================
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# DSC Format Codes (Category)
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# Per ITU-R M.493-15 Table 1
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# =============================================================================
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FORMAT_CODES = {
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102: 'ALL_SHIPS', # All ships call
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112: 'INDIVIDUAL', # Individual call
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114: 'INDIVIDUAL_ACK', # Individual acknowledgement
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116: 'GROUP', # Group call (including geographic area)
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120: 'DISTRESS', # Distress alert
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123: 'ALL_SHIPS_URGENCY_SAFETY', # All ships urgency/safety
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}
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# Valid ITU-R M.493 format specifiers
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VALID_FORMAT_SPECIFIERS = {102, 112, 114, 116, 120, 123}
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# Valid EOS (End of Sequence) symbols per ITU-R M.493
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VALID_EOS = {117, 122, 127}
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# Category priority (lower = higher priority)
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CATEGORY_PRIORITY = {
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'DISTRESS': 0,
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'ALL_SHIPS_URGENCY_SAFETY': 2,
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'ALL_SHIPS': 5,
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'GROUP': 5,
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'INDIVIDUAL': 5,
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'INDIVIDUAL_ACK': 5,
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}
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# =============================================================================
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# Nature of Distress Codes
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# Per ITU-R M.493-15 Table 3
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# =============================================================================
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DISTRESS_NATURE_CODES = {
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100: 'UNDESIGNATED', # Undesignated distress
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101: 'FIRE', # Fire, explosion
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102: 'FLOODING', # Flooding
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103: 'COLLISION', # Collision
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104: 'GROUNDING', # Grounding
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105: 'LISTING', # Listing, in danger of capsizing
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106: 'SINKING', # Sinking
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107: 'DISABLED', # Disabled and adrift
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108: 'ABANDONING', # Abandoning ship
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109: 'PIRACY', # Piracy/armed robbery attack
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110: 'MOB', # Man overboard
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112: 'EPIRB', # EPIRB emission
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}
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# =============================================================================
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# Telecommand Codes (First and Second)
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# Per ITU-R M.493-15 Tables 4-5
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# =============================================================================
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TELECOMMAND_CODES = {
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# First telecommand (type of subsequent communication)
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100: 'F3E_G3E_ALL', # F3E/G3E all modes (VHF telephony)
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101: 'F3E_G3E_DUPLEX', # F3E/G3E duplex
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102: 'POLLING', # Polling
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103: 'UNABLE_TO_COMPLY', # Unable to comply
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104: 'END_OF_CALL', # End of call
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105: 'DATA', # Data
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106: 'J3E_TELEPHONY', # J3E telephony (SSB)
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107: 'DISTRESS_ACK', # Distress acknowledgement
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108: 'DISTRESS_RELAY', # Distress relay
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109: 'F1B_J2B_FEC', # F1B/J2B FEC NBDP telegraphy
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110: 'F1B_J2B_ARQ', # F1B/J2B ARQ NBDP telegraphy
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111: 'TEST', # Test
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112: 'SHIP_POSITION', # Ship position request
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113: 'NO_INFO', # No information
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118: 'FREQ_ANNOUNCEMENT', # Frequency announcement
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126: 'NO_REASON', # No reason given
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# Second telecommand (additional info)
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200: 'F3E_G3E_SIMPLEX', # Simplex VHF telephony requested
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201: 'POLL_RESPONSE', # Poll response
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}
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# Full 0-127 telecommand lookup (maps unknown codes to "UNKNOWN")
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TELECOMMAND_CODES_FULL = {i: TELECOMMAND_CODES.get(i, "UNKNOWN") for i in range(128)}
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# Format codes that carry telecommand fields
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TELECOMMAND_FORMATS = {112, 114, 116, 120, 123}
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# Minimum symbols (after phasing strip) before an EOS can be accepted
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MIN_SYMBOLS_FOR_FORMAT = 12
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# =============================================================================
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# DSC Symbol Definitions
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# Per ITU-R M.493-15
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# =============================================================================
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# Special symbols
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DSC_SYMBOLS = {
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120: 'DX', # Dot pattern (synchronization)
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121: 'RX', # Phasing sequence RX
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122: 'SX', # Phasing sequence SX
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123: 'S0', # Phasing sequence S0
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124: 'S1', # Phasing sequence S1
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125: 'S2', # Phasing sequence S2
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126: 'S3', # Phasing sequence S3
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127: 'EOS', # End of sequence
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}
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# =============================================================================
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# MID (Maritime Identification Digits) Country Mapping
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# First 3 digits of MMSI identify the country
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# Per ITU MID table (partial list of common codes)
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# =============================================================================
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MID_COUNTRY_MAP = {
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# Americas
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'201': 'Albania',
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'202': 'Andorra',
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'203': 'Austria',
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'204': 'Azores',
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'205': 'Belgium',
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'206': 'Belarus',
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'207': 'Bulgaria',
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'208': 'Vatican City',
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'209': 'Cyprus',
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'210': 'Cyprus',
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'211': 'Germany',
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'212': 'Cyprus',
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'213': 'Georgia',
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'214': 'Moldova',
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'215': 'Malta',
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'216': 'Armenia',
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'218': 'Germany',
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'219': 'Denmark',
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'220': 'Denmark',
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'224': 'Spain',
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'225': 'Spain',
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'226': 'France',
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'227': 'France',
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'228': 'France',
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'229': 'Malta',
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'230': 'Finland',
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'231': 'Faroe Islands',
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'232': 'United Kingdom',
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'233': 'United Kingdom',
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'234': 'United Kingdom',
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'235': 'United Kingdom',
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'236': 'Gibraltar',
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'237': 'Greece',
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'238': 'Croatia',
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'239': 'Greece',
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'240': 'Greece',
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'241': 'Greece',
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'242': 'Morocco',
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'243': 'Hungary',
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'244': 'Netherlands',
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'245': 'Netherlands',
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'246': 'Netherlands',
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'247': 'Italy',
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'248': 'Malta',
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'249': 'Malta',
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'250': 'Ireland',
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'251': 'Iceland',
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'252': 'Liechtenstein',
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'253': 'Luxembourg',
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'254': 'Monaco',
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'255': 'Madeira',
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'256': 'Malta',
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'257': 'Norway',
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'258': 'Norway',
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'259': 'Norway',
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'261': 'Poland',
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'262': 'Montenegro',
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'263': 'Portugal',
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'264': 'Romania',
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'265': 'Sweden',
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'266': 'Sweden',
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'267': 'Slovakia',
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'268': 'San Marino',
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'269': 'Switzerland',
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'270': 'Czech Republic',
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'271': 'Turkey',
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'272': 'Ukraine',
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'273': 'Russia',
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'274': 'North Macedonia',
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'275': 'Latvia',
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'276': 'Estonia',
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'277': 'Lithuania',
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'278': 'Slovenia',
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'279': 'Serbia',
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# North America
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'301': 'Anguilla',
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'303': 'USA',
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'304': 'Antigua and Barbuda',
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'305': 'Antigua and Barbuda',
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'306': 'Curacao',
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'307': 'Aruba',
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'308': 'Bahamas',
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'309': 'Bahamas',
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'310': 'Bermuda',
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'311': 'Bahamas',
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'312': 'Belize',
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'314': 'Barbados',
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'316': 'Canada',
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'319': 'Cayman Islands',
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'321': 'Costa Rica',
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'323': 'Cuba',
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'325': 'Dominica',
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'327': 'Dominican Republic',
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'329': 'Guadeloupe',
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'330': 'Grenada',
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'331': 'Greenland',
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'332': 'Guatemala',
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'334': 'Honduras',
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'336': 'Haiti',
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'338': 'USA',
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'339': 'Jamaica',
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'341': 'Saint Kitts and Nevis',
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'343': 'Saint Lucia',
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'345': 'Mexico',
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'347': 'Martinique',
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'348': 'Montserrat',
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'350': 'Nicaragua',
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'351': 'Panama',
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'352': 'Panama',
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'353': 'Panama',
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'354': 'Panama',
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'355': 'Panama',
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'356': 'Panama',
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'357': 'Panama',
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'358': 'Puerto Rico',
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'359': 'El Salvador',
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'361': 'Saint Pierre and Miquelon',
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'362': 'Trinidad and Tobago',
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'364': 'Turks and Caicos',
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'366': 'USA',
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'367': 'USA',
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'368': 'USA',
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'369': 'USA',
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'370': 'Panama',
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'371': 'Panama',
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'372': 'Panama',
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'373': 'Panama',
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'374': 'Panama',
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'375': 'Saint Vincent and the Grenadines',
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'376': 'Saint Vincent and the Grenadines',
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'377': 'Saint Vincent and the Grenadines',
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'378': 'British Virgin Islands',
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'379': 'US Virgin Islands',
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# Asia
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'401': 'Afghanistan',
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'403': 'Saudi Arabia',
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'405': 'Bangladesh',
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'408': 'Bahrain',
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'410': 'Bhutan',
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'412': 'China',
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'413': 'China',
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'414': 'China',
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'416': 'Taiwan',
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'417': 'Sri Lanka',
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'419': 'India',
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'422': 'Iran',
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'423': 'Azerbaijan',
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'425': 'Iraq',
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'428': 'Israel',
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'431': 'Japan',
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'432': 'Japan',
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'434': 'Turkmenistan',
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'436': 'Kazakhstan',
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'437': 'Uzbekistan',
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'438': 'Jordan',
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'440': 'South Korea',
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'441': 'South Korea',
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'443': 'Palestine',
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'445': 'North Korea',
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'447': 'Kuwait',
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'450': 'Lebanon',
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'451': 'Kyrgyzstan',
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'453': 'Macao',
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'455': 'Maldives',
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'457': 'Mongolia',
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'459': 'Nepal',
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'461': 'Oman',
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'463': 'Pakistan',
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'466': 'Qatar',
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'468': 'Syria',
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'470': 'UAE',
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'471': 'UAE',
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'472': 'Tajikistan',
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'473': 'Yemen',
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'475': 'Yemen',
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'477': 'Hong Kong',
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'478': 'Bosnia and Herzegovina',
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# Oceania
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'501': 'Adelie Land',
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'503': 'Australia',
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'506': 'Myanmar',
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'508': 'Brunei',
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'510': 'Micronesia',
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'511': 'Palau',
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'512': 'New Zealand',
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'514': 'Cambodia',
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'515': 'Cambodia',
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'516': 'Christmas Island',
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'518': 'Cook Islands',
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'520': 'Fiji',
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'523': 'Cocos Islands',
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'525': 'Indonesia',
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'529': 'Kiribati',
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'531': 'Laos',
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'533': 'Malaysia',
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'536': 'Northern Mariana Islands',
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'538': 'Marshall Islands',
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'540': 'New Caledonia',
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'542': 'Niue',
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'544': 'Nauru',
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'546': 'French Polynesia',
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'548': 'Philippines',
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'550': 'Timor-Leste',
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'553': 'Papua New Guinea',
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'555': 'Pitcairn Island',
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'557': 'Solomon Islands',
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'559': 'American Samoa',
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'561': 'Samoa',
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'563': 'Singapore',
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'564': 'Singapore',
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'565': 'Singapore',
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'566': 'Singapore',
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'567': 'Thailand',
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'570': 'Tonga',
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'572': 'Tuvalu',
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'574': 'Vietnam',
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'576': 'Vanuatu',
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'577': 'Vanuatu',
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'578': 'Wallis and Futuna',
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# Africa
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'601': 'South Africa',
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'603': 'Angola',
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'605': 'Algeria',
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'607': 'St. Paul and Amsterdam Islands',
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'608': 'Ascension Island',
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'609': 'Burundi',
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'610': 'Benin',
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'611': 'Botswana',
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'612': 'Central African Republic',
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'613': 'Cameroon',
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'615': 'Congo',
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'616': 'Comoros',
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'617': 'Cabo Verde',
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'618': 'Crozet Archipelago',
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'619': 'Ivory Coast',
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'620': 'Comoros',
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'621': 'Djibouti',
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'622': 'Egypt',
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'624': 'Ethiopia',
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'625': 'Eritrea',
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'626': 'Gabon',
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'627': 'Ghana',
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'629': 'Gambia',
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'630': 'Guinea-Bissau',
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'631': 'Equatorial Guinea',
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'632': 'Guinea',
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'633': 'Burkina Faso',
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'634': 'Kenya',
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'635': 'Kerguelen Islands',
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'636': 'Liberia',
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'637': 'Liberia',
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'638': 'South Sudan',
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'642': 'Libya',
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'644': 'Lesotho',
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'645': 'Mauritius',
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'647': 'Madagascar',
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'649': 'Mali',
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'650': 'Mozambique',
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'654': 'Mauritania',
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'655': 'Malawi',
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'656': 'Niger',
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'657': 'Nigeria',
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'659': 'Namibia',
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'660': 'Reunion',
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'661': 'Rwanda',
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'662': 'Sudan',
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'663': 'Senegal',
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'664': 'Seychelles',
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'665': 'Saint Helena',
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'666': 'Somalia',
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'667': 'Sierra Leone',
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'668': 'Sao Tome and Principe',
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'669': 'Swaziland',
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'670': 'Chad',
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'671': 'Togo',
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'672': 'Tunisia',
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'674': 'Tanzania',
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'675': 'Uganda',
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'676': 'Democratic Republic of Congo',
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'677': 'Tanzania',
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'678': 'Zambia',
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'679': 'Zimbabwe',
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# South America
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'701': 'Argentina',
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'710': 'Brazil',
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'720': 'Bolivia',
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'725': 'Chile',
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'730': 'Colombia',
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'735': 'Ecuador',
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'740': 'Falkland Islands',
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'745': 'Guiana',
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'750': 'Guyana',
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'755': 'Paraguay',
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'760': 'Peru',
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'765': 'Suriname',
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'770': 'Uruguay',
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'775': 'Venezuela',
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}
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# =============================================================================
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# VHF Channel Frequencies (MHz) for DSC follow-up
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# =============================================================================
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VHF_CHANNELS = {
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6: 156.300, # Intership safety
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8: 156.400, # Commercial working
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9: 156.450, # Calling
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10: 156.500, # Commercial working
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12: 156.600, # Port operations
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13: 156.650, # Bridge-to-bridge navigation safety
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14: 156.700, # Port operations
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16: 156.800, # Distress, safety and calling (VHF voice)
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67: 156.375, # UK small craft safety
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68: 156.425, # Marina/yacht club
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70: 156.525, # DSC distress, safety and calling
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71: 156.575, # Port operations
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72: 156.625, # Intership
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73: 156.675, # Port operations
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74: 156.725, # Port operations
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77: 156.875, # Intership
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}
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# =============================================================================
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# DSC Modulation Parameters
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# =============================================================================
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DSC_BAUD_RATE = 1200 # 1200 bps per ITU-R M.493
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# FSK tone frequencies (Hz) on 1700 Hz subcarrier
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DSC_MARK_FREQ = 2100 # B (mark) - binary 1
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DSC_SPACE_FREQ = 1300 # Y (space) - binary 0
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# Audio sample rate for decoding
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DSC_AUDIO_SAMPLE_RATE = 48000
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# Frame structure
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DSC_DOT_PATTERN_LENGTH = 200 # 200 bits of alternating pattern
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DSC_PHASING_LENGTH = 7 # 7 symbols phasing sequence
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DSC_MESSAGE_MAX_SYMBOLS = 180 # Maximum message length in symbols
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