I really suggest that you test your multiplexer before installing it on your boat. You will learn about it and you will make a more confident installation. The 1st thing you can do when you receive a multiplexer (this is general for all the models) is to use a USB cable and power the multiplexer from a PC using that cable. Then you can check if the NMEA3WIFI network was created. You can connect to that network using the password 12345678 and typing 192.168.4.1 on the navigation bar of a web browser. Then you can use Simulate Mode. You will see the green light on P1 to blink rapidly and, from time to time, you will also see the the green light on P2 to blink. If you did not change the default settings the blue led will also blink. Here is the meaning of the leds
- green P1 led blinks when a fictitious sentence for GPS, wind and depth are sent
- green P2 led blinks when a fictitious AIS sentence is sent (as only 2 moored boats are sent, the sending is sparse)
- blue led blinks when there is WiFi data going out and coming in
If you have Navionics or OpenCPN or any other application capable of receiving WiFi nmea0183 data, this is the time to test. You need" to go" to the island of Lesbos in Greece to see "your" boat and 2 AIS targets.
You could also test reception/transmission by USB, UDP and TCP using Debug Mode and the the Nmea0183Tester tool but that is not the purpose of this post. Actually I would like to post here 2 videos that completely test the hardware of the multiplexer. I ask users to make this test before they suggest to return the multiplexer to me (which is very rare I must say

- 1 - sends a chunk of 500 zeros and ones on P3 at 9600 baud and blinks red light
- 2 - reads P1 and checks if the exact 500 zeros and ones are received in the same order
- 3 - repeats 1 and 2 at 38400 baud
- 4 - if no single error is detected it blinks P1 green led
- 5 - does 1 2 3 and 4 but this time it reads P2
- 6 - sends the chunk of 500 zeros and ones to the SeaTalk1 bus (DATA line) and blinks red ST1 led
- 7 - reads the DATA line and checks if it can read what it is sending. If yes, it blinks the green ST1 led
- 8 - goes to 1
If you also want to test the ST1 bus you need to power the multiplexer from the 12V and GND screw connectors:
You can use even a small 9V battery for this test. I have a small Gel battery when I do my tests:
I hope this is useful, Regards, Luis