AIS Port Confusion

[GeorgeSmith]

Help,
I'm a little confused on how to tie in my AIS data into Open CPN.
1. Do I need to use a second USB to serial converter on a second USB port?
2. What does AIS port (shared) mean on the NMEA data source tab mean?

[Viking Sailor]

George,

Some AIS receivers accept the NMEA formatted output of the GPS receiver and combine the GPS and AIS data in the output of the AIS receiver. Thus, the GPS and AIS can share a single PC input port. Normally the output data from the GPS runs at a 9600 baud rate and the AIS data output runs at 34800 baud. So, when using a combined AIS/GPS source it is necessary to configure the PC to accept the AIS baud rate of 34800. And, if you want to us a USB port then a serial converter will be necessary.

[GeorgeSmith]

Thanks,
It's as I thought. I'm using a Horizon VHF with a AIS receiver built in. I'm feeding this 3400 baud signal to my Garmin chartplotter. The garmin has two NMEA outputs. So Ill take the merged output of the garmin into Open CPN.
Is this why under the GPS tab the NMEA data source says: AIS (port shared)?

Thanks
George

[yachtvalhalla]

Originally Posted by GeorgeSmith

Is this why under the GPS tab the NMEA data source says: AIS (port shared)?

Yes.

Terry