NMEA 0183 Issues

Begin with a Problem Statement

Basic configuration without enough interconnection points and with single points of failure

Some Challenges of Device Interconnection

What is the solution when you have more devices that need GPS input than you have GPS sources?

What is the solution when you have devices that need GPS and fathometer input, but one GPS or one autopilot fails?

To Err is Human, to Really Confuse Things takes a Computer

What does Windows think is on a port?
How do you connect multiple sensors (e.g., GPS and fathometer) to a single computer port?

Building Blocks of NMEA 0183 Solutions

Expanders:  take 1 NMEA talker output and fan it out into multiple outputs

Expander/switches:  Take 2 NMEA talker outputs, and use the preferred one only if the backup is active, fanning out to several outputs. If the preferred output fails, use the backup as source

Multiplexers: take multiple NMEA talkers and concentrate it into one output (see USB example)