Abstract: A subsea data and power transmission apparatus includes primary and secondary open magnetic circuits with coils for wireless data and power transfer between a drilling tool and a drilling rig. The primary magnetic circuit is U-shaped and the secondary is O-shaped. Both magnetic systems are electrically insulated. The electrical signal and power are transferred from one magnetic circuit to another through an air or water gap between the magnetic circuits. The U-shaped and O-shaped magnetic circuits allow communication and power transfer remotely with no mechanical or electrical connectors.