Here is some information that others might find useful. I recently acquired a B&G Zeus 3S chartplotter and wanted QTVLM to receive the instrument data from the NMEA bus over wifi. qtvlm can get NMEA data over TCP, but it only understand the old NMEA 1863 protocol. The B&G chartplotter is connected to a nmea 2000 bus, so initially it wasn't clear how I would be able to send the data to QTVLM. It turns out the B&G chartplotter has a built-in TCP service that can either send data in the NMEA 2000 format or 1863 format:
1. Enable the Wi-Fi hotspot on the Zeus 3s chartplotter. Note the IP address of the Zeus 3s chartplotter.
2. In the Zeus 3s network settings, enable the NMEA 1863 service.
3. On the laptop where qtvlm is running, connect the Wi-Fi to the Zeus 3s Wi-Fi hotspot.
4. In qtvlm, go to configuration, then NMEA connections. In the inbound channel, enable TCP, and set the IP address of the Zeus 3s chartplotter. Keep the default TCP port.
In summary, qtvlm can get NMEA data over Wi-Fi directly from the B&G Zeus 3s chartplotter. No intermediate nmea gateway is required.
However, it looks like a gateway is required to send the active waypoint from qtvm to the chartplotter
