NMEA 0183: Everything you need to know!

NMEA 0183 is a standard used to enable communication between marine electronic devices. This standard has become a cornerstone in marine electronics and is used by everything from GPS devices to autopilots and echo sounders. In this blog post, we will delve deeper into what NMEA 0183 is, how it works, and why it is so important.

What is NMEA 0183?

NMEA stands for National Marine Electronics Association, and 0183 is a specific standard they have developed to ensure that different marine electronic devices can communicate with each other. The standard defines a common language that the devices use to exchange data, allowing them to work together seamlessly.

How does NMEA 0183 work?

NMEA 0183 uses a simple serial communication protocol where data is sent in the form of sentences. Each sentence begins with a $ sign and ends with a checksum to ensure that the data has not been corrupted during transmission. Here is an example of an NMEA 0183 sentence:

$GPGGA,123519,4807.038,N,01131.000,E,1,08,0.9,545.4,M,46.9,M,,*47

This sentence contains information about a GPS position, including time, latitude, longitude, and altitude.

Common NMEA 0183 sentences and their meanings

There are many different types of sentences in the NMEA 0183 standard, each with its own specific meaning. Here are some of the most common:

Here are the 10 most common NMEA 0183 abbreviations:

• GGA: Global Positioning System Fix Data - GPS fix data.
• GLL: Geographic Position, Latitude/Longitude - Geographic position, latitude/longitude.
• GSA: GPS DOP and Active Satellites - GPS DOP and active satellites.
• GSV: GPS Satellites in View - GPS satellites in view.
• RMC: Recommended Minimum Navigation Information - Recommended minimum navigation information.
• VTG: Track Made Good and Ground Speed - Track and ground speed.
• ZDA: Time and Date - Time and date.
• HDG: Magnetic Heading, Deviation, Variation - Magnetic heading, deviation, and variation.
• HDT: Heading, True - True heading.
• DBT: Depth Below Transducer - Depth below transducer.

These abbreviations are used to describe different types of data sent between devices, such as GPS receivers, echo sounders, autopilots, and other instruments.

Why is NMEA 0183 important?

NMEA 0183 is important because it enables interoperability between different manufacturers' devices. This means that a GPS device from one manufacturer can communicate with an autopilot from another manufacturer, giving boat owners the flexibility to choose the best devices for their needs without worrying about compatibility issues.

How to connect NMEA 0183 devices

There are several ways to connect NMEA 0183 devices to ensure effective communication and data transfer between them. Here are some of the most common methods:

1. Direct connection: Devices can be directly connected to each other using NMEA 0183 cables. This is the simplest method, but it requires that the devices are compatible and have the correct connections. Make sure that transmitting cables are connected to receiving ones to ensure proper data transfer.
   
   
2. Multiplexer: An NMEA 0183 multiplexer, such as Actisense PRO-NDC-1E2K, can be used to connect multiple devices to a single device. The multiplexer collects data from multiple sources and sends it to a receiver.
   
   
3. Gateway: An NMEA 0183 to NMEA 2000 gateway, such as Actisense WGX-1-ISO, enables wireless data transfer from the NMEA 2000 network to devices like laptops, tablets, or smartphones via Wi-Fi. It converts data between NMEA 0183 and NMEA 2000, allowing devices from both standards to communicate effectively.
   
   
4. Isolation: It is recommended to use isolation when connecting NMEA 0183 devices to a PC to avoid ground loops that can damage both the PC and the NMEA 0183 device.
   
   
5. Battery banks: When connecting NMEA 0183 devices between different battery banks, it is important to ensure that the negative terminals are connected to avoid potential differences that can cause problems.

Differences between NMEA 0183 and RS422

NMEA 0183 is a standard for communication between marine electronic devices. It has evolved through several versions, with the latest version being 4.11. NMEA 0183 specifications (version 2 and later) should at a minimum meet the requirements of the computer standard RS422 (Standard EIA-422-A). RS422 uses differential driving, which means it uses two wires to send data, making it less sensitive to interference and allowing for longer cable lengths.

NMEA 0183 originally used single-ended driving but has later been updated to use differential driving (RS422). RS422 is not strictly compatible with RS232, but most RS422 drivers work as single-ended drivers if only one output wire is used. In summary, the main difference is that RS422 uses differential driving to reduce interference and allow for longer cable lengths, while NMEA 0183 originally used single-ended driving but has been updated to use the RS422 specification.

The future of NMEA 0183

Although NMEA 0183 is still widely used, the newer NMEA 2000 standard has begun to take over. NMEA 2000 offers higher data transfer speeds and support for more devices on the same network. Despite this, NMEA 0183 is likely to remain relevant for many years to come, especially for older devices and systems.

If you want to see the complete list of NMEA 0183 abbreviations, you can find it at the link below.

https://web.nmea.org/External/WCPages/WCWebContent/webcontentpage.aspx?ContentID=364