The earlier model humminbirds were networkable right? LIke the 898 998 etc?
Humminbird used an accessory called INTERLINK before there was Ethernet. INTERLINK shared waypoints and a GPS antenna. INTERLINK was discontinued when the XX9 models came out.
The 1197 was the first unit with an Ethernet port, but was not usable until Ethernet was activated with the XX8 units in the 800, 900, and 1100 series plus the HD version in the 700 series. Those units did not have Ethernet either until the software was released to have Ethernet (Ethernet menus and function). That happened on March 5, 2011. After Ethernet was activated you had the choice of INTERLINK or Ethernet with the XX8 models but could not use both.
Cross-sharing sonar technologies did not start until the XX9 (999ci HD SI Combo) Ethernet models (software update)and along with that some functions of the XX8 series could be shared, but the XX8 series will not cross-share.
Cross-share as an example is a Sonar model displaying Side Imaging from a Side Imaging unit.
The Helix units replaced the XX9 models, just uses a name instead of a number for the model.
No different than Lowrance going from the 300 series to 500 series to HDS and now Carbon.