It's sometimes useful to verify that either AIS or GPS data is being properly received by the WatchMate.
To do this on a WatchMate 850, 750 or 670, first turn it off. Then switch it back on by pressing the power button while holding the top button at the same time. At the top of the screen will be "Data Received from Port 1". The raw NMEA data stream will be displayed on the screen. You can pause the display by pressing and holding any button. When you release the button the data display will continue. If you see all dots (".") then it probably means you have the port set to the wrong device type or a wiring problem. Restart the AISWatchMate normally and check the settings for that port.
To exit from the raw data display, press the power button. To view the data stream on port 2, turn the AISWatchMate on by holding the 2nd button from the top while pressing the power button.
You can also look at the NMEA 0183 data stream on all WatchMate and XB Transponder products over USB or WiFi using the vmAIS Configuration and Status Utility