What Is Kplex? Complete Guide to the Powerful Data Streaming Tool

What Is Kplex?

If you’ve ever managed marine electronics or worked with NMEA data streams, chances are you’ve heard of Kplex. But what exactly is Kplex, and why is it such a powerful data streaming tool in the maritime world?

In simple terms, Kplex is an open-source, lightweight, and efficient NMEA-0183 multiplexer designed for handling marine data streams. It enables you to collect, filter, combine, and redistribute navigational data between various marine devices and applications seamlessly.

Whether you’re a hobbyist sailor, system integrator, or a professional marine engineer, Kplex simplifies how data flows between GPS units, AIS transponders, chart plotters, and onboard computers — ensuring reliable and synchronized communication.

Understanding Kplex: The Basics

At its core, Kplex acts as a data traffic controller for NMEA sentences. It gathers input from multiple data sources (serial, TCP, UDP, or file inputs) and distributes them to various outputs according to defined rules.

Key Functions of Kplex

• Data Multiplexing: Combine multiple NMEA input streams into one coherent output.
• Filtering & Routing: Filter specific NMEA sentences or route them to selected outputs.
• Protocol Conversion: Translate data between different communication protocols (e.g., TCP → UDP).
• Data Duplication: Replicate streams for redundancy or monitoring.
• Custom Configuration: Create flexible setups with configuration files or command-line options.

How Kplex Works: A Simplified Breakdown

Kplex sits between your data-producing devices (like GPS, wind sensors, AIS) and data-consuming applications (like OpenCPN or Signal K). It receives messages from inputs, processes them based on user-defined rules, and forwards them efficiently.

Example Setup:

This flexibility allows marine systems to communicate in real-time without bottlenecks or data conflicts.

Why Use Kplex? Top Benefits

1. Lightweight and Efficient

Written in C, Kplex is extremely resource-friendly, making it ideal for embedded systems like the Raspberry Pi or marine navigation computers.

2. Open Source and Free

Kplex is licensed under the GPL, ensuring transparency, community contributions, and continuous improvement.

3. Highly Configurable

Users can define input/output parameters, filters, and priorities through a simple text configuration file.

4. Platform Independent

Kplex runs on Linux, macOS, and Windows, offering broad compatibility.

5. Reliable Marine-Grade Performance

Its robustness and error handling make it perfect for continuous maritime use — even under harsh network conditions.

Installing Kplex: Step-by-Step Guide

Here’s a quick overview of how to install and set up Kplex on Linux:

Step 1: Install Dependencies

sudo apt-get update
sudo apt-get install build-essential

Step 2: Download Kplex Source

git clone https://github.com/stripydog/kplex.git

Step 3: Build and Install

cd kplex
make
sudo make install

Step 4: Configure Inputs and Outputs

Edit the configuration file (/etc/kplex.conf or a custom file):

[in]
name=gps
device=/dev/ttyUSB0
baud=4800

[out]
name=tcpout
mode=tcp
port=10110

Then start Kplex:

sudo kplex -f /etc/kplex.conf

Kplex Configuration Explained

A Kplex configuration file defines how data flows between sources and destinations.
Each section starts with [in], [out], or [filter] tags.

Common Parameters:

This modular setup makes it easy to adjust routing and filtering without changing hardware.

Common Use Cases for Kplex

1. Data Aggregation

Combine multiple NMEA data sources into a single stream for navigation software.

2. Remote Monitoring

Forward vessel data over TCP/IP to shore-based systems or cloud dashboards.

3. Data Logging

Record navigation and sensor data for later analysis or compliance.

4. Redundant Output

Send identical streams to multiple destinations (e.g., chart plotter and backup computer).

Kplex vs. Alternatives

Feature	Kplex	Signal K	nmead
Open Source
Lightweight
Supports NMEA 0183
Supports NMEA 2000
Web Dashboard
Custom Filters

Verdict:
If your use case revolves around NMEA 0183 data handling with minimal overhead, Kplex remains one of the most efficient and reliable tools available.

Troubleshooting Common Kplex Issues

Q: Kplex won’t start — what should I check?
A: Verify configuration file syntax and ensure ports are not already in use.

Q: I’m not seeing any data in OpenCPN.
A: Check your TCP port (default 10110) and confirm network firewall rules.

Q: Can I run multiple Kplex instances?
A: Yes — as long as each uses different ports and configuration files.

Best Practices for Using Kplex

• Keep configuration files backed up before making changes.
• Use specific filters to reduce unnecessary traffic.
• Log outputs for debugging and compliance.
• Combine Kplex with Signal K for web-based visualization.
• Regularly update to the latest stable version.

FAQs About Kplex

Is Kplex still maintained?

Yes. Although updates are infrequent, the tool remains stable and widely used in the marine community.

Can I use Kplex with Signal K or OpenCPN?

Absolutely. It integrates smoothly with both, serving as a reliable data bridge.

Does Kplex support NMEA 2000?

Not directly — it focuses on NMEA 0183, but can work alongside converters that handle NMEA 2000.

Conclusion: Why Kplex Stands Out

In the world of marine data streaming, Kplex continues to be a trusted, open-source solution. It’s lightweight, flexible, and battle-tested for NMEA 0183 communication — making it the go-to multiplexer for hobbyists and professionals alike.

Whether you’re integrating multiple navigation systems or building a smart boat setup, Kplex offers the simplicity and reliability you need to manage your data streams effectively.