`
`NATIONAL MARINE ELECTRONICS ASSOCIATION
`
`NMEA 0183
`
`STANDARD FOR INTERFACING MARINE ELECTRONIC DEVICES
`
`Version 2.01
`
`August I, 1994
`
`

`

`

`

`NMEA 0183 - Standard For Interfacing Marine Electronic Devices
`
`CONTENTS
`
`PREFACE
`
`1. INTRODUCTION
`
`2. MANUFACTURER’S DOCUMENTATION
`
`3. HARDWARE SPECIFICATION
`
`4. DATA TRANSMISSION
`
`5. DATA FORMAT PROTOCOL
`
`6. DATA CONTENT
`
`7. APPLICATIONS
`
`APPENDIX I - Sentences Not Recommended For New Designs
`
`APPENDIX 11 - Glossary of Terms
`
`APPENDIX III - Manufacturer’s Mnemonic Codes
`
`INDEX
`
`

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`

`

`NMEA 0183 - Standard For Interfacing Marine Electronic Devices
`
`Preface .......................................................... 1
`Availability and Updates of the Standard ................................. 1
`1. Introduction .................................................... 2
`1.1 Scope ................................................... 2
`1.2 Intended Application and Limitations on Use ...................... 2
`1.3 Definitions ............................................... 2
`1.4 References ............................................... 2
`2. Manufacturer’s Documentation ...................................... 3
`3. Hardware Specification ............................................ 3
`3.1 Interconnecting Wire
`....................................... 3
`3.2 Conductor Definitions ....................................... 4
`3.3 Electrical Connections/Shield Requirements ....................... 4
`3.4 Connector
`............................................... 4
`3.5 Electrical Signal Characteristics
`............................... 4
`3.5.1 Signal State Definitions ............................... 4
`3.5.2 TALKER Drive Circuits ............................... 4
`3.5.3 LISTENER Receive Circuits ............................ 4
`3.5.4 Electrical Isolation ................................... 5
`3.5.5 Maximum Voltage on Bus .............................. 5
`4. Data Transmission ............................................... 6
`5. Data Format Protocol ............................................. 6
`5.1 Characters ............................................... 6
`5.1.1 Reserved Characters .................................. 6
`5.1.2 Valid Characters
`.................................... 6
`5.1.3 Undefined Character
`................................. 6
`5.1.4 Character Symbols ................‘ ................... 7
`5.2 Fields
`.................................................. 7
`5.2.1AddressField7
`5.2.2 Data Fields ........................................ 7
`5.2.3 Checksum Field ..................................... 8
`5.3 Sentences ............................................... 9
`5.3.1 Approved Sentences ................................. 9
`5.3.2 Query Sentences .................................... 11
`5.3.3 Proprietary Sentences ................................ 11
`5.3.4 Valid Sentences .................................... 12
`5.3.5 Sentence Transmission Timing ......................... 12
`5.3.6 Additions to Approved Sentences ........................ 12
`6. Data Content .................................................. 13
`TABLE 1 - RESERVED CHARACTERS
`........................... 13
`TABLE 2 - VALID CHARACTERS ............................... 13
`TABLE 3 - CHARACTER SYMBOL TABLE ......................... 14
`TABLE 4 - TALKER IDENTIFIER MNEMONICS .................... 15
`TABLE 5 - APPROVED SENTENCE FORMATTERS
`................. 16
`TABLE 6 - FIELD TYPE SUMMARY ............................. 18
`6.3 Approved Sentences
`....................................... 20
`
`

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`NMEA 0183 - Standard For Interfacing Marine Electronic Devices
`
`Preface
`
`NMEA Interface Standards are intended to serve the public interest by facilitating interconnection
`and interchangeability of equipment, minimizing misunderstanding and confusron between
`manufacturers, and assisting purchasers in selecting compatible equrpment.
`
`Standards are adopted by NMEA without regard to whether or not their adoption may involve
`patents on articles, materials or processes. By such action, NMEA does not assume any liability to
`any patent owner, nor does it assume any obligation whatever to parties adopting these Standards.
`
`This Standard defines electrical signal requirements, data transmission protocol and timing, and
`specific sentence formats for a 4800 baud serial data bus. Each bus may have only a Single TALK~
`ER but may have multiple LISTENERs.
`
`Because of differences in baud rate and other transmission parameters, NMEA 0183 data is not
`directly compatible with NMEA 0180 or NMEA 0182 Standards.
`
`Equipment that is specified by IMO to meet the SOLAS regulations is governed by the requirements
`of IEC 1162-1: Digital Interfaces. Maritime Navigation and Radiocommunications Eguipmcntand
`Svstems. The IEC Standard is aligned closely with the NMEA 0183 Standard. Where possrbie,
`differences between the two documents, and sections that pertain specifically to IEC requirements,
`are indicated herein by the symbol "“‘" in the margin.
`
`Availability and Updates of the Standard
`
`This standard may be modified by action of the NMEA Interface Standards Committee as the
`need arises.
`
`Updates to this Standard are published periodically in:
`
`Marine Electronics - The Official Journal of the NMEA
`National Marine Electronics Association
`P.O. Box 3435
`
`New Bern, NC 28564-3435
`USA.
`
`For additional or updated capies
`of this standard, contact:
`
`NMEA Executive Director
`P.O. Box 3435
`New Bern, NC 28564-3435
`U.S.A.
`
`TelephOne: (919) 637-7759 '
`FAX: (919) 637-8136
`
`For technical information, contact:
`
`Chairman, NMEA 0183 Standards
`Committee:
`
`Frank Cassidy
`Datamarine International, Inc.
`53 Portside Drive
`Pocasset, MA 02559
`U.S.A.
`
`Telephone: (508) 563-7151
`
`

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`

`NMEA 0183 - Standard For Interfacing Marine Electronic Devices
`
`1. Introduction
`
`1.1 Scope
`
`This standard is developed to permit ready and satisfactory data communication between electronic
`marine instruments, navigation equipment and communications equipment when interconnected v1a
`an appropriate system.
`
`1.2 Intended Application and Limitations on Use
`
`This standard is intended to support one—way serial data transmission from a single TALIGER to one
`or more LISTENERs. This is data in printable ASCII form and may include information such as
`position, speed, depth, frequency allocation, etc. Typical messages might be 20 to a maximum of 79
`characters in length and generally require transmission no more often than once per second.
`
`The electrical definitions in this standard are not intended to accommodate high:bandwidth
`applications such as radar or video imagery. or intensive database or file transfer applications.
`
`Since there is no prevision for guaranteed delivery of messages and only limited error checking
`capability, this standard should be used with caution in critical applications.
`
`1.3 Definitions
`
`1.3.1 General
`
`Common terms are defined in Appendix II, Glossary, of this Standard. Wherethere is a conflict
`terms shall be interpreted wherever possible in accordance with the references in Section 1.4.
`
`1.3.2 TALKERs
`
`A TALKER is any device which sends data to other devices within this standard. The type of
`TALKER is identified by a 2-character mnemonic as listed in Section 6.2 (Table 4).
`
`1.3.3 LISTENERS
`
`A LISTENER is any device which receives data from another device within this standard.
`
`1.4 References
`
`1.4.1 American National Standards Institute:
`1. ANSI X 3.15 1976 ANSI Character Structure and Character Parity Sense for
`Serial-by-Bit Communication
`2. ANSI X 3.16 1976 ANSI Bit Sequencing of the ANS Code for Information Interchange
`in Serial-By-Bit Data Transmission.
`3. ANSI X 3.4 1977 ANSI Code for Information Interchange
`
`

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`NMEA 0183 - Standard For Interfacing Marine Electronic Devices
`
`1.4.2 Electronic Industries Association Standards:
`A. EIA-422-A December 1978 (CCI'IT X.27/V.11)
`
`1.4.3 International Electrotechnical Commission:
`3, rue de Varembe
`P.O. Box 131
`1211 Geneva 20
`SWITZERLAND
`A. IEC 945, Marine Navigational Eguipment - General Reguirements
`B. IEC 1162-1: Digital Interfaces, Maritime Navigation and Radiocommunications
`Eguipment and Systems
`
`1.4.4 American Practical Naviv=ator, Defense Mapping Agency HydrographiCITopographic Center,
`Publication No. 9, DMA Stock No. NVPUB9V1, Volumes I and II
`
`1.4.5 Interface Control Document, Navstar GPS Space Segmenthavigation User Interface.
`Rockwell International Corporation Document No. ICD-GPS-200 Revision B (November
`30, 1987)
`
`2. Manufacturer’s Documentation
`
`Operator's manuals or other apprOpriate literature provided for equipment that is intended to meet
`the requirements of this standard shall contain the following information:
`
`1. Identification of the A and B signal lines.
`2. The output drive capability as a TALKER.
`3. A list of approved sentences, noting unused fields, PrOprietary sentences transmitted
`as a TALKER. and transmission interval for each sentence.
`'
`4. The load requirements as a LISTENER.
`5. A list of sentences and associated data fields that are required as a LISTENER.
`6. The current software and hardware revision if this is relevant to the interface.
`7. An electrical description or schematic of the LlSTEN'ER/TALKER input/output
`circuits citing actual components and devices used, including connector type and part
`number.
`
`8. The Version No. and Date of Update of the standard for which compliance is
`assured.
`
`3. Hardware Specification
`
`One TALKER and multiple LISTENERS may be connected in parallel over an interconnecting wire.
`The number of LISTENERS depends on the output capability and input drive requirements of
`individual devices.
`
`3.1 Interconnecting Wire
`
`

`

`NMEA 0183 - Standard For Interfacing Marine Electronic Devices
`
`3.2 Conductor Definitions
`
`The conductors referred to in this standard are the signal lines "A" and "B", and shield.
`
`3.3 Electrical Connections/Shield Requirements
`
`All signal line “A" connections are connected in parallel with all device "A" connections and all signal
`line “B" connections are connected in parallel with all device "B" connections. The shield should be
`connected to the TALKER chassis and should not be connected at any LISTENER. However, the
`shield should be continuous (unbroken) between all LISTENERs.
`
`3.4 Connector
`
`No standard connector is specified. Wherever possible readily available commercial connectors
`should be used. Manufacturers shall provide means for user identification of the connectors used.
`
`3.5 Electrical Signal Characteristics
`
`This section describes the electrical characteristics of transmitters and receivers.
`
`3.5.1 Signal State Definitions
`
`The idle, marking, logical "1", OFF or stop bit state is defined by a negative voltage on line "A" with
`respect to line "B".
`
`The active, spacing, logical “0", ON or start bit state is defined by a positive voltage on line "A" with
`respect to line "B".
`
`Note that the above "A" with respect to "B“ levels are inverted from the voltage input/output
`requirements ofstandard UARTs and that many line drivers and receivers provide a logic mvers:on-
`
`3.5.2 TALKER Drive Circuits
`
`No provision is made for more than a single TALKER to be connected to the bus. The drive circuit
`used to provide the signal "A" and the return "B" shall meet, at a minimum. the requirements of
`EIA-422-A (December 1978).
`
`3.5.3 LISTENER Receive Circuits
`
`Multiple LISTENERS may be connected to a single TALKER. The LISTENER receive circuit shall
`consist ofan optoisolator and should have protective circuits to limit current, reverse bias and power
`dissipation at the optodiode as shown in Figure 1. Reference is made to example circuits in Section
`7.0 of this Standard.
`
`The receive circuit shall be designed for operation with a minimum differential input voltage of 2.0
`Volts and shall not take more than 2.0 mA from the line at that voltage.
`
`

`

`NMEA 0183 - Standard For Interfacing Marine Electronic Devices
`
`For reasons of compatibility with equipment designed to earlier versions of this standard, it is noted
`that the "idle, marking, logical “1", OFF or stop bit state" had previously been defined to be in the
`range -15 to + 0.5 Volts. The "active, spacing, logical "0", ON or start .bit state“ was defined to be
`in the range +4.0 to +15 Volts while sourcing not less than 15 mA.
`
`
`PROTECTIVE
`
`CIRCUITS
`
`
`.........................................
`
`..........................................................
`
`
`
`
`CIRCUITS
`
`BIA—422
`
`PROTECTIVE
`
`LISTENER N0.
`
`1
`
`MM
`
`3.5.4 Electrical Isolation
`
`Within a LISTENER there shall be no direct electrical connection between the signal line, "A",
`return line, "B", or shield and ship's ground or power.
`Isolation from ship‘s ground IS reqmred.
`
`3.5.5 Maximum Voltage on Bus
`
`The maximum applied voltage between signal lines ”A“ and "B” and between either line and Ground
`will be in accordance with the BIA-422 specification.
`
`For protection against miswiring and for use with earlier TALKER designs, all receive circuit devices
`should be capable of withstanding 15 volts between signal lines "A" and "B" and between either line
`and ground for an indefinite period.
`
`

`

`NMEA 0183 - Standard For Interfacing Marine Electronic Devices
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`4. Data Transmission
`
`Data is transmitted in serial asynchronous form in accordance with ANSI standards (reference
`paragraph 1.4.1). The first bit is a start bit and is followed by data bits, least-sigmficant—bit first as
`illustrated by Figure 2. The following parameters are used:
`
`Baud rate
`Data bits
`Parity
`Stop bits
`
`4800
`8 (d7 = 0)
`None
`One
`
`D0
`
`D1
`
`D2
`
`D3
`
`D4
`
`D5
`
`D6
`
`D7
`
`
`
`STOP
`BIT
`
`START
`BIT
`
`DATA BITS
`
`FIGURE 2
`
`5. Data Format Protocol
`
`5.1 Characters
`
`All transmitted data shall be interpreted as ASCII characters. The most significant bit of the 8-bit
`character shall always be transmitted as zero (d7 = 0).
`
`5.1.1 Reserved Characters
`
`The reserved character set consists ofthose ASCII characters shown in Section 6.1 (Table 1). These
`characters are used for specific formatting purposes, such as sentence and field delimiting, and may
`not be used in data fields.
`
`5.1.2 Valid Characters
`
`The valid character set consists of all printable ASCII characters (HEX 20 to HEX 7E) except those
`defined as reserved characters. Section 6.1 (Table 2) lists the valid character set.
`
`5.1.3 Undefined Character
`
`ASCII values not specified as either "reserved characters" or "valid characters" are excluded and may
`not be transmitted at any time.
`
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`

`NMEA 0183 - Standard For Interfacing Marine Electronic Devices
`
`5.1.4 Character Symbols
`
`When individual characters are used in this standard to define units of measure, indicate the type
`of data field, type of sentence, etc. they will be interpreted according to the character symbol table
`in section 6.1 (Table 3).
`
`5.2 Fields
`
`A field consists of a string of valid characters, or no characters (null field), located between two
`appropriate delimiter characters.
`
`5.2.1 Address Field
`
`An address field is the first field in a sentence and follows the "S" delimiter, it serves to define the
`start of sentence. Characters within the address field are limited to digits and upper case letters.
`The address field may not be a null field. Only sentences with the following three types of address
`fields may be transmitted:
`'
`
`5.2.1.1 Approved Address Field
`
`Approved address fields consist of five characters defined by this standard. The first two characters
`are the TALKER Identifier, listed in Section 6.2 (Table 4). The next three characters form the
`Sentence Formatter used to define the format and the type of data. Section 6.2 (Table 5) and
`Appendix I list approved Sentence Formatters.
`
`5.2.1.2 Query Address Field
`
`The query address consists of five characters and is used for the purpose of requesting transmission
`of a specific sentence on a separate bus from an identified TALKER.
`
`The first two characters are the TALKER Identifier of the device requesting data, the next two
`characters are the TALKER Identifier ot' the device being addressed and the final character is the
`query character "Q".
`
`5.2.1.3 Proprietary Address Field
`
`The proprietary address field consists of the proprietary character "P" followed by a three-character
`Manufacturer's Mnemonic Code, used to identify the TALKER issuing a proprietary sentence, and
`any additional characters as required. A list of valid Manufacturer's Mnemonic Codes is contained
`in Appendix III.
`
`5.2.2 Data Fields
`
`Data Fields in approved sentences follow a “," delimiter and contain valid characters in accordance
`with the formats illustrated in Section 6.2 (Table 6). Data fields in proprietary sentences contain
`only valid characters but are not defined by this standard.
`
`

`

`NMEA 0183 - Standard For Interfacing Marine Electronic Devices
`
`located within a sentence by observing the field delimiters ",". Therefore it is essential for the
`LISTENER to locate fields by counting delimiters rather than ecunting total number of characters
`received from the start of the sentence.
`
`5.2.2.1 Variable Length fields
`
`Although some data fields are defined to have fixed length, many are of variable length in order to
`allow devices to convey information and to provide data with more or less precision, according to
`the capability or requirements of a particular device.
`
`Variable length fields may be alpha-numeric or numeric fields. Variable numeric fields may contain
`a decimal point and may contain leading or trailing "zeros".
`
`5.2.2.2 Data Field Types
`
`Data fields may be alpha, numeric, alphanumeric, variable length, fixed length, fixedivariablc (with
`a portion fixed in length while the remainder varies). Some fields are constant, With their value
`dictated by a Specific sentence definition. The allowable field types are summarized in Section 6.2
`(Table 6), Field Type Summary.
`
`5.2.2.3 Null Fields
`
`A null field is a field of length zero, i.e. no characters are transmitted in the field. Null fields shall
`be used when the value is unreliable or not available.
`
`For example, if heading information were not available, sending data of "000" is misleading because
`a user cannot distinguish between "000" meaning no data and a legitimate heading of 900 .
`However, a null field, with no characters at all, clearly indicates that no data is being transmitted.
`
`Null fields with their delimiters can have the following appearance depending on where. they are
`located in the sentence:
`
`I!
`
`II
`
`u
`
`"I"
`.
`
`",<CR><LF>"
`
`The ASCII NULL character (HEX 00) shall n_ot be used as the null field.
`
`5.2.3 Checksum Field
`
`A checksum field may optionally be transmitted in any sentence. However sorne approved sentences
`specifically require the checksum field. The checksum field is the last field in a sentence and follows
`the checksum delimiter character "‘“.
`
`The checksum is the 8-bit exclusive OR (no start or stop bits) of all characters in the sentence,
`including "," deiimiters, between but not including the_"3" and the "" delimiters.
`
`The hexadecimal value of the most significant and least significant 4 bits of the result are converted
`to two ASCII characters (0-9, A-F) for transmission. The most significant character is transmitted
`first.
`
`

`

`NMEA 0183 - Standard For Interfacing Marine Electronic Devices
`
`5.3 Sentences
`
`This section describes the general structure of sentences. Details of Specific sentence formats are
`found in Section 6.3 and Appendix I. Some sentences may specify restrictions beyond the general
`limitations given in this part of the standard. Such restrictions may include defining some fields as
`fixed length, numeric or text only, required to be non-null, transmitted with a certain frequency, etc.
`
`The maximum number of characters in a sentence shall be 82, consisting of a maximum of 79
`characters between the starting delimiter "$" and the terminating <CR> <LF>.
`
`The minimum number of fields in a sentence is one (1). The first field shall be an address field
`coutaining the identity of the TALKER and the sentence formatter which specifies the number of
`data fields in the sentence, the type of data they contain and the order in which the data fields are
`transmitted. The remaining portion of the sentence may contain zero or multiple data fields.
`
`The maximum number of fields allowed in a single sentence is limited only by the maximum sentence
`length of 82 characters. Null fields may be present in the sentence and shall always be used if data
`for that field is unavailable.
`
`All sentences begin with the sentence start delimiter character "S“ and end with the sentence
`termination delimiter <CR> <LF>.
`
`5.3.1 Approved Sentences
`
`Approved sentences are those designed for general use and detailed in this Standard. Approved
`sentences are listed in Section 6.3 and Appendix I. Preferred sentences are contained in Section 6.3
`and these sentences should be used wherever possible. Appendix I contains sentences that may be
`phased-out of use, are not recommended for new designs, but may be met in practice.
`
`An approved sentence contains, in the order shown, the following elements:
`
`<address field>
`[","<data field>]
`
`HEX 24 - Start of sentence
`TALKER identifier and sentence formatter
`Zero or more data fields
`
`[","<data field>]
`["‘"<checksum field>]
`<CR> <LF>
`
`Optional checksum field
`Hex DD 0A - End of sentence
`
`

`

`NMEA 0183 - Standard For Interfacing Marine Electronic Devices
`
`5.3.1.1 Approved Sentence Structure
`
`The following provides a summary explanation of the approved sentence structure:
`
`$aaccc,c—-c*hh< CR> <LF>
`
`ASCII
`
`HEX
`
`DESCRIPTION
`
`
`
` "3" 24 Start of Sentence.
`
`
`
`aaccc
`
`Address Field. Alphanumeric characters identifying type of TALKER,
`and Sentence Formatter. The first two characters identify the
`TALKER. The last three are the Sentence Formatter mnemonic code
`identifying the data type and the string format of the successive fields.
`Mnemonics will be used as far as possible to facilitate readouts by
`users.
`
`"."
`
`2C
`
`Field delimiter. Starts each field except address and checksurn fields.
`Ifit is followed by a null field, it is all that remains to indicate no data
`in a field.
`
`C-"C
`
`"*"
`
`hh
`
`Data Sentence block. Follows address field and is a series of data
`fields containing all of the data to be transmitted. Data field sequence
`is fixed and identified by 3rd and subsequent characters of the address
`field (the “Sentence Formatter"). Data fields may be of variable length
`and are preceded by delimiters ",".
`
`2A
`
`Optional Checksum Delimiter. Follows last data field of the sentence.
`It indicates that the following two alpha-numeric characters show the
`HEX value of the CHECKSUM.
`
`Optional Checksurn Field. The absolute value calculated by
`exclusive-OR’ing the 8 data him (no start bits or stop bits) of each
`character in the Sentence, between, but excluding "S" and "‘". The
`hexadecimal value of the most significant and least significant 4 bits of
`the result are converted to two ASCII characters (09, A-F) for
`transmission. The most significant character is transmitted first. The
`"CHECKSUM" field is optional. except when indicated as mandatory.
`
`<CR><LF> 0D 0A
`
`Terminates Sentence.
`
`

`

`NMEA 0183 - Standard For Interfacing Marine Electronic Devices
`
`5.3.2 Query Sentences
`
`Query sentences are intended to request Approved sentences to be transmitted in a form of two
`way communication. The use of query sentences implies that the LISTENER shall have the
`capability of being a TAIKER with its own bus.
`
`The approved Query sentence contains, in the order shown, the following elements:
`
`HEX 24 - Start of sentence
`
`<aa>
`<aa>
`
`TALKER Identifier of requester
`TALKER Identifier for device from which data is being requested
`Query character identifies Query address
`Data field delimiter
`Approved sentence formatter of data being requested
`<CCC>
`["""'<checlcsum field>] Optional checksum field
`<CR><LF>
`HEX 0D 0A - End of sentence
`
`5.3.2.1 Reply To Query Sentence
`
`The reply to a Query sentence is the Approved sentence that was requested. The use of Query
`sentences requires cooperation between the devices that are interconnected, a reply to a Query
`sentence is not mandatory and there is no Specified time delay between the receipt of a query and
`the reply.
`
`5.3.3 Preprietary Sentences
`
`Proprietary sentences provide a means for manufacturers to use the sentence structure definitions
`of this standard to transfer data which does not fall within the scepe of approved sentences. This
`will generally be for one of the following reasons:
`'
`
`1. Data is intended for another device from the same manufacturer, is device specific, and not
`in a form or of a type of interest to the general user;
`
`2. Data is being used for test purposes prior to the adoption of approved sentences;
`
`3. Data is not of a type and general usefulness which merits the creation of an approved
`sentence.
`
`A proprietary sentence contains. in the order shown, the following elements:
`
`"5"
`"P"
`<aaa>
`[<valid characters>]
`[“‘"<checksum field>]
`<CR> <LF>
`
`Hex 24 - Start of sentence
`Hex 50 - Proprietary sentence ID
`Manufacturer’s Mne monic code
`Manufacturer’s data
`Optional checksum ficId
`Hex 0D 0A - End of sentence
`
`

`

`NMEA 0183 - Standard For Interfacing Marine Electronic Devices
`
`Beyond limiting overall sentence length and requiring the use of only valid characters, details of
`proprietary data fields will not be included in this standard and need not be submitted for approval.
`However it is required that such sentences be published in the manufacturer's manuals for reference.
`
`5.3.4 Valid Sentences
`
`Approved sentences, Query sentences and Preprietary sentences are the only valid sentences.
`Sentences of any other form are non-valid and shall not be transmitted on the bus.
`
`5.3.5 Sentence Transmission Timing
`
`Frequency of sentence transmission when specified shall be in accordance with the approved
`sentence definitions (Section 6.3 and Appendix I). When not
`specified,
`the rate should be
`consistent with the basic measurement or calculation cycle but generally not more frequently
`than once per second.
`
`It is desirable that sentences be transmitted with minimum inter-character spacing, preferably as a
`near continuous burst, but under no circumstance shall the time to complete the transmission of a
`sentence be greater than 1 second.
`
`5.3.6 Additions to Approved Sentences
`
`In order to allow for improvements or additions, future revisions of this Standard may modify
`existing sentences by adding new data fields after the last data field but be fore the optional checksum
`delimiter character "*" and checksum field. LISTENERS should determine the end of the sentence
`by recognition of <CR> <LF> and “"" rather than by counting field delimiters. The checksum value
`should be computed on all received characters between, but not including, "S" and "“" whether or not
`the LISTENER recognizes all fields.
`
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`

`NMEA 0183 - Standard For Interfacing Marine Electronic Devices
`
`6. Data Content
`
`6.1 Character Definitions
`
`TABLE 1 - RESERVED CHARACTERS
`HEX
`DECIMAL
`0D
`13
`0A
`10
`24
`36
`2A
`42
`2C
`44
`21
`33
`5C
`92
`5E
`94
`7E
`126
`
`Carriage return } End of sent-
`Line feed
`} tence delimiter
`Start of sentence delimiter
`Checksum field delimiter
`Field delimiter
`Reserved for future use
`Reserved for future use
`Reserved for future use
`Reserved for future use
`
`<CR>
`<LF>
`
`"
`"
`
`34
`35
`
`37
`38
`39
`40
`41
`
`43
`
`1.151 D2
`Space 20
`32
`Reserved
`22
`23
`#
`Reserved
`%
`25
`&
`26
`27
`28
`29
`Reserved
`+
`2B
`Rese rved
`2D
`213
`2F
`30
`31
`32
`33
`34
`35
`36
`37
`38
`39
`3A
`3B
`3C
`3D
`3E
`
`45
`46
`47
`48
`49
`50
`51
`52
`53
`54
`55
`56
`57
`58
`59
`60
`61
`62
`
`<
`=
`>
`
`TABLE 2 - VALID CHARACTERS
`E m
`40
`64
`@
`41
`65
`A
`42
`66
`B
`43
`67
`C
`44
`68
`D
`45
`69
`E
`46
`70
`F
`47
`71
`G
`48
`72
`H
`49
`73
`I
`4A
`74
`J
`4B
`75
`K
`4C
`76
`L
`4D
`77
`M
`413
`78
`N
`4F
`79
`O
`50
`80
`P
`5 1
`81
`Q
`52
`82
`R
`53
`83
`S
`54
`84
`T
`55
`85
`U
`56
`86
`V
`5 7
`87
`W
`58
`88
`X
`59
`89
`Y
`5A .
`90
`Z
`SB
`91
`[
`Reserved
`]
`5D
`Reserved
`
`93
`
`m D_EC
`60
`96
`‘
`61
`97
`a
`62
`98
`b
`63
`99
`c
`64
`100
`d
`65
`101
`e
`66
`102
`f
`67
`103
`g
`68
`104
`h
`69
`105
`i
`6A
`106
`j
`6B
`107
`k
`6C
`108
`1
`6D
`109
`m
`6E
`1 IO
`:1
`6F
`1 1 1
`o
`70
`1 12
`p
`71
`1 I3
`q
`72
`1 14
`r
`73
`1 15
`s
`74
`1 16
`t
`75
`1 17
`u
`76
`118
`v
`77
`1 19
`w
`78
`120
`x
`79
`121
`y
`- 7A
`122
`z
`7B '
`123
`{
`7C
`124
`:
`7D
`12.5
`}
`Reserved
`
`

`

`NMEA 0183 - Standard For Interfacing Marine Electronic Devices
`
`6.1 Character Definitions
`
`(continued)
`
`TABLE 3 - CHARACTER SYMBOL TABLE
`
`Status symbol; Yes; Data Valid; Warning Flag Clear; Auto; Amperes
`Alphabet character variable A through Z or a through 2
`Bars (pressure, 1000 Mb equal 1 Std. Atm.); Bottom
`Celsius (Degrees); Course-up
`Valid characters; Calculating
`Degrees (of Arc)
`Error; East; Engine
`Fathoms
`Feet
`
`Great Circle; Green
`Good
`
`Compass Heading; Head-up; Hertz; Humidity
`Hours; HEX number
`Inches
`
`Input operation completed
`Kilometers; Kin/hour
`Kilograms
`Left; Local; Lost Target
`Latitude; Liters; Liters/second
`Meters; Meters/second; Magnetic; Manual; Cubic Meters
`Minutes; message
`Nautical miles; Knots; North; North-up; Newton
`Numeral; address
`Purple; Proprietary (only when following "5"); Position sensor; Percent
`Query; Target-BeingAcquired
`Right; Rhumb line; Red; Relative; Reference; Radar Tracking; Rev/min
`South; Statute miles; Statute milesfhour; Shaft
`Seconds
`
`Time difference; True; Track; Tracked-Target
`Test
`
`Dead Reckoning Estimate
`Sign. if minus "-" (HEX 2D)
`Data invalid; No; Warning Flag Set; Manual; Volt
`West; Water; Wheelover
`Numeric Character variable
`Longitude
`Time
`
`
`
`
`
`NECK€<I=qummwotfiz’zazflfiwquHp-mmomfijmdnnwprp
`
`

`

`NMEA 0183 - Standard For Interfacing Marine Electronic Devices
`
`6.2 Field Definitions
`
`TABLE 4 - TALKER IDENTIFIER MNEMONICS
`
`(Address Characters 1 and 2)
`
`
`
` . TALKER DEVICE IDENTIFIER
`
`AUTOPILOT:
`
`AG"
`General
`AP
`Magnetic
`COMMUNICATIONS: Digital Selective Calling (DSC) CD“
`Data Receiver
`CR
`Satellite
`CS‘
`Radio-Telephone (MF/HF)
`CI"
`Radio—Telephone (VI-IF)
`CV'
`Scanning Receiver
`CX‘
`DE
`DECCA Navigator
`DF‘
`Direction Finder
`Electronic Chart Display & Information System (ECDIS) EC
`Emergency Position Indicating Beacon (EPIRB)
`EP"
`Engineroom Monitoring Systems
`ER
`Global Positioning System (GPS)
`GP
`HEADING SENSORS: Compass, Magnetic
`HC“
`Gyro, North Seeking
`HE‘
`Gyro, Non-North Seeking
`HN
`Integrated Instrumentation
`11
`Integrated Navigation
`IN
`LORAN:
`Loran A
`LA
`Loran C
`LC
`OMEGA Navigation System
`OM
`Proprietary Code
`P
`Radar and/or ARPA
`RA‘
`Sounder, depth
`SD“
`Electronic positioning system, other/general
`SN
`Sounder, scanning
`SS
`Turn Rate Indicator
`TI“
`TRANSIT Navigation System
`TR
`VELOCITY SENSORS: Doppler, other/general
`VD‘
`Speed Log, Water, Magnetic
`VM
`Speed Log, Water, Mechanical
`VW
`YX
`ZA
`ZC
`ZQ
`ZV
`WI
`
`Transducer
`TIMEKEEPERS, TIMEIDATE: Atomic Clock
`Chronometer
`Quartz
`Radio Update, WWV or WWVH
`Weather Instruments
`
`‘Designated by IEC for use with IMO maritime electronic devices. This is the minimum
`requirement for equipment that is specified by IMO in the SOLAS Convention (1974. as
`
`

`

`NMEA 0183 - Standard For Interfacing Marine Electronic Devices
`
`6.2 Field Definitions
`
`TABLE 5 - APPROVED SENTENCE FORMATTERS
`
`AAM - Waypoint Arrival Alarm ........................................... 20
`ALM - GPS Almanac Data ............................................... 20
`APB - Autopilot Sentence "B" ............................................. 21
`*ASD - Autopilot System Data
`............................................. 21
`BEC - Bearing & Distance to Waypoint - Dead Reckoning ........................ 21
`BOD - Bearing - Origin to Destination ....................................... 22
`BWC - Bearing & Distance to Waypoint
`..................................... 22
`BWR - Bearing & Distance to Waypoint - Rhumb Line
`.......................... 22
`BWW - Bearing - Waypoint to Waypoint ..................................... 22
`DBT - Depth Below Transducer ............................................ 22
`DCN - Decca Position ................................................... 23 .
`*DPT - Depth .......................................................... 23
`DSC - DSC Information ................................................. 23
`DTM - Datum Reference
`................................................ 23
`*FSI - Frequency Set Information
`........................................ _.
`.
`. 23
`GBS - GPS Satellite Fault Detection
`........................................ 24
`GGA - Global Positioning System Fix Data
`................................... 25
`GLC - Geographic Position - Loran-C ....................................... 25
`GLL - Geographic Position - Latitude/Longitude
`............................... 2.5
`GRS - GPS Range Residuals .............................................. 26
`GSA - GPS DOP and Active Satellites ....................................... 26
`GST - GPS Pseudorange Noise Statistics ..................................... 27
`GSV - GPS Satellites in View ............................................. 27
`GXA - TRANSIT Position ................................................ 28
`'HDG - Heading, Deviation & Variation ...................................... 28
`‘HDT - Heading - True ............