[GPSNavX]

A few things to get an AIS receiver up and running on your Mac. Make sure you have installed the Keyspan driver first (link below). If you have just the AIS connected to the Keyspan adapter you want to pick the port /dev/cu.KeySerial1 in the AIS panel Settings drawer (accessed via "Connect" on the "AIS/RADAR" menu). Set the rate to 38400. Uncheck "Use GPS Port". If AIS targets are present you will see them list in the AIS panel and you will see !AIVDM NMEA messages in the AIS panel Monitor drawer after pressing Start.

http://www.keyspan.com/downloads-files/u...ialv24.zip

More help on AIS..

http://www.gpsnavx.com/MacENC/help/connectingais.htm