Actually there are two Garmin pucks there and they are both NMEA 0183. I have a 2006C and a 3210 that are years old but still work just fine.
That 24" radar dome took over for the largest on a C-Dory when John on C-Lou retired his old Furuno. It was Garmin's first marine radar for consumers and my kid worked at a place that sold them getting me a good discount. But, like Dusty said at the time when folks were making fun of me - the bigger the array, the better the definition.
The 3' length wasn't the biggest difference to me when I switched from the CD22. The 10" extra beam took the most getting used to at the dock. That old boat has a lot of things that need to be fixed up but she still serves me well and with the new Suzi (just like Daydream's!) it will continue to serve me for the few more years I can trust myself to manage it safely. Then I will sell it as is and be content with what it brings.