I don't think you can network Echo series with GPSMAP series. The new Echomap UHD can share sonar with another Echo UHD
Thats what I thought. Early on, I was looking to match the two units together so it would be a similar price range as the Simrad GO units and still give radar capability.
Maybe with the hub it would work as I never looked into it....
Anyways, I would contact Garmin as it seems certain Echomaps don’t even talk with each other depending on what version it was (ie Ulta vs Plus etc). They seem to call it out on their site which leads me to believe it is not all backwards compatible.