Simrad SC90, Installation Manual

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338
419050/B
About NMEA and standard datagram formats
Topics
About the NMEA datagram formats, page 338
National Marine Electronics Association (NMEA), page 338
NMEA sentence structure, page 339
Standard NMEA 0183 communication parameters, page 340
About the NMEA datagram formats
The SC90 can send and receive information to and from several different peripherals.
All transmissions take place as
datagrams with data sentences. Each datagram has a
defined format and length.
The NMEA 0183 standard is the most common protocol used to receive and transmit
data to and from peripheral sensors. A parametric sentence structure is used for all
NMEA data.
The sentence start with a “$” delimiter, and represent the majority of approved sentences
defined by the standard. This sentence structure, with delimited and defined data files, is
the preferred method for conveying information.
For more information about the NMEA standard, the format and the data sentences, refer
to their official publications. Their document
NMEA 1083 - Standard for interfacing
marine electronic devices explains the formats in detail. The document can be obtained
from NMEA.
Note
Two phrases are in general use to describe basic transfer unit associated with a
packet-switched network; "telegram" and "datagram". In this publication, we use the
phrase "datagram".
National Marine Electronics Association (NMEA)
The National Marine Electronics Association (NMEA) has defined communication
standards for maritime electronic equipment, and the SC90 Fish finding sonar supports
these standards for communication with external sensors and peripheral systems.
The most common standard is the NMEA 0183. The National Marine Electronics
Association describes it as follows:
The NMEA 0183 Interface Standard defines electrical signal requirements, data
transmission protocol and time, and specific sentence formats for a 4800 baud serial
data bus. Each bus may have only one talker but many listeners.
Simrad SC90 Installation Manual