I'm looking for a sonar that will send NMEA depth data out and receive NMEA GPS data in. I also want a unit that works with the 4pin CV20-TM transducer. According to the installation and user manuals (page 4 of http://static.garmin.com/pumac/echoM...llation_EN.pdf ), the EchoMap Plus 45cv is exactly what I'm looking for. Can anyone confirm that it will work with an external GPS? Will it also send NMEA depth data?