"Are you sure there is an RXA on the intelliducer? A least on the NMEA 0183 the only data transfer wires are the TXA and TXB (which are a differential pair)...

I am using a harware serial.

Thanks man!

This is the bare minimum that I am using to…"

"Dragos from the manual the minimum water depth is 1m ! But it should work on shallower waters, but you should no trust those values.
I am connecting my intelliducer to an Arduino Mega, I used the TX/B from the sonar to the RX1 on the arduino board.…"

"TJC, what are the voltage levels from the intelliducer? 0-5V?

Thanks man!
Rafael"

"Hi TCIII AVD, from the Garmin Manual you should use the TXA as the default choice... Did you have any problem for not using it?

"If your NMEA 0183-compliant device has only one receiving wire (Rx), connect it to the gray wire (Tx/A) from the…"