The inductive mooring line modem consists of the head-end modem (HEM) and one or more sub-surface modems (SSM). Each instrument on the mooring line system is connected to an SSM, which communicates inductively with the HEM through the mooring cable.

The main features of the inductive mooring line modem are a fast communication rate along the mooring line, shock protected ferrites, no pre-deployment configuration required, an automated instrument discovery mechanism, and an intelligent addressing mechanism that conserves power. A comprehensive set of system commands is available to query or command the instruments to identify themselves, take a sample, and transmit data. Instruments may be addressed individually, in sub-groups,or all at once.

The SSM is available as an integral option for RBR instruments, attached as the battery end-cap via a coupler. Alternatively, use it as a standalone cabled version for serial connection to an RBR instrument in combination with the RBRfermata battery canister, or to a third-party instrument, such as ADCP.