This module allows bidirectional wifi communication between your smart-phone, tablet or laptop and your boat instrumentation. The system has 2 opto-isolated full Nmea 0183 compatible input ports. One port is used to receive instrument data at the rate of 4.800 or 9.600 baud. The other port has an adjustable baud rate from 4.800 up to 38.400 and can receive AIS data. The 2 streams of data may be combined and transmitted over wifi to connected receivers. In addition, the module also has an output NMEA 0183 port with an adjustable baud rate from 4.800 up to 38.400. The output port can transmit data received by the 2 input ports or by wifi. You can use this module in different ways. You can use it with a PC running navigation software such as OpenCPN or you can use it with several free apps for Android or Ios. In addition you can get Sonar Chart Live maps on your Navionics Boating HD app.


Power Supply Voltage: 7V up to 16V DC
Power Consumption:
   less than 70mA with Wifi ON or
   30mA with Wifi OFF
Nmea 183 Input Ports: P1 and P2 - optical isolated
Nmea 183 Output Port: P3 - RS-422 compatible
Baud Rates:
  P1 (4800 or 9600)
  P2 and P3 (4800, 9600, 19200 or 38400)


The power supply (usually 12V) and the serial ports use screw connectors. The connectors have printed labels in the PCB. The labels for the power supply are 12V (positive) and GND (negative). The 2 serial input ports have labels A1 and B1 (port 1) and A2 and B2 (port 2). If your Nmea data is available though a differential port you connect the A (or +) terminal to the module A1 (or A2) and the B (or -) terminal to the module B1 (or B2). If your Nmea data is available through a single ended port (such as RS-232) you connect the Output terminal to the module A1 (or A2) and the Ground (or common) terminal to the module B1 (or B2). The output serial port uses a 3-way screw connector with labels A3 B3 and GND. If the receiving device has an opto-isolated port, you connect A3 to the A (or +) terminal of the receiving device and B3 to the B (or -) terminal of the receiving device. If the input port of the receiving device is not opto-isolated you should take special attention to the connections. You should connect A3 to the input terminal of the receiving device and not use B3. If, in addition, the multiplexer and the receiving device do not share a common ground, you should connect GND to the common (or ground) terminal of the receiving device.


The module is totally wifi configurable. When you supply power to the module for the first time, it will start with factory settings and it automatically creates a wifi network named NMEA2WIFI. You should disconnect your smartphone (or your PC) from other networks and connect to this NMEA2WIFI network using the password 12345678. When you are connected you write in the navigation bar of your browser and you will receive a web page which allows you to fully configure your module.


If you set a network name and a password for your module and later on you forget these settings, you can at any time, return to the default factory settings by pressing, and holding down for about 3 seconds, the switch labelled as SW1 on the main PCB (printed circuit board). For more support, please visit: or use the email <luis at vela-navega dot com>. In this website there is also a dedicated forum to the Nmea2Wifi multiplexer.


This web page is the response you receive when you type in the navigation bar of your browser after you connect to the NMEA2WIFI network. Note that the page will not respond to the commands SET, HARD RESET and UPDATE as it is not running in the multiplexer. Please see the sections in this site that describe these functions.


The Nmea2Wifi multiplexer is available in 2 versions: TH (Through Hole) and SMD (Surface Mounting Devices). They have the same functionality and only differ in the manufacturing technology. There are small differences shown in the following pictures. One difference is the position of the USB micro or mini socket. In both cases the cover box can not be mounted when you use a USB cable. SMD units use a mini USB socket and a mini USB cable is included. In future revisions of the SMD hardware a micro USB socket will be used instead of the mini socket.

Multiplexer Box TH Version SMD Version