The KT-74 is a direct replacement only if ADS-B is not being utilized. The KT-74 is designed to fit into an existing KT-76A/C & KT-78A tray. However to utilize the ADS-B feature of the KT-74, a secondary connector and new tray will need to be installed.

The KT-74 has two Molex edge connectors. The primary connector can use the same contact positions and are electrically compatible with the KT-76A & KT-78A (if properly wired). A secondary connector would need to be installed to utilize ADS-B functions, resulting in a necessary second hole in the rack to accommodate the connector.