NMEA FAQ's: What is NMEA?

NMEA - stands for the National Marine Electronics Association

NMEA Interface Standards are intended facilitate interconnection and interchangeability of equipment digital date, minimizing misunderstanding and confusion between manufacturer's equipment and provide safe and reliable equipment communication for the mariner.

Among other important goals and objectives, NMEA defines electrical signal requirements, data transmission protocol and time, and specific sentence formats- in which your standard instrumentation and navigation manufacturers use. The GOOD news, is that standards in general, makes is easy for your marine instrumentation and nav equipment to USE information.

The BAD news, is that when standards "change", you may need to "change" with them.

NMEA FAQ's: What is a NMEA compliant device?

NMEA is a combined data and electrical spec defining communication between marine electronic devices such as sonars, echo sounder, anemometer (wind speed and direction), gyrocompass, autopilot, GPS receivers and many other types of instrumentation.

So, as you look around your boat, your instrumentation display, sensor sensor and GPS reciever - irregardless of the manufacturer is most likely NMEA compliant. It can share the same "language".

NMEA FAQ's: What is some examples of NMEA devices?

• Depth Sounder
• Animometer
• Speed Log
• GPS
• Auto Pilot
• Engine Instrumentation

NMEA FAQ's: What do I need to know about NMEA?

NMEA has provided a standardized protocol to allow communication between marine navigation devices. Be sure to go to the NMEA.org website for more information. NMEA communication can get technical - but here is what you need to know:

The communication between navigation devices uses NMEA messages -- and these messages contain NMEA sentences. Depending on how your electronics are configured, devices can act as originators or senders of NMEA data. This means that they SEND information OUT. Sometimes, these are called NMEA Talkers. Other devices can act as recievers, or consumers of NMEA data. They are called NMEA Listeners.

Many of your electronic devices (instrumentation) also have options to connect via RS232 or USB with computers. In this case, your computer will act as NMEA Listener. In that role, your computer will have to know how to handle the NMEA datastream.

HandHELM(tm) processes your NMEA messages / sentences. The information from these sentences can be displayed on your laptop, pocket PC, touch screen tablet or Blackberry.

NMEA FAQ's: What does NMEA have TWO different standards?

Ok, now we're getting to the part of NMEA that can affect your wallet. The best resource for NMEA information -- is directly on the NMEA.org website. Other websites, that promote themselves as experts, tend to get this NMEA 0183 and NMEA 2000 confused. Since the NMEA.org site can get a bit technical, I'm going to de-mystify this for you.

NMEA 0183 (the OLD standard used for marine electronics built PRIOR to 2005)
...is an interface "standard" used to define

• 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. This standard is intended to support one-way serial data transmission from a single talker to one or more listeners. This data is in printable ASCII form and may include information such as position, speed, depth, frequency allocation, etc.

NMEA 2000 (the NEW standard used for marine electronics built AFTER 2005)

NMEA 2000® standard contains the requirements of a serial data communications network to inter-connect marine electronic equipment on vessels. The standard describes a low-cost moderate capacity bi-directional, multi-transmitter/multi-receiver instrument network to interconnect marine electronic devices.

It is multi-master and self configuring, and there is no central network controller. Equipment designed to this standard will have the ability to share data, including commands and status with other compatible equipment over a single channel. It is based on CAN (Controller Area Network). All NMEA 2000® products must be certified by NMEA. Although this standard is 50 times faster than NMEA 0183, it is not intended to support high-bandwidth applications such as video.