Features of the system, which ensure reliability and security, include signal technology, forward error correction techniques, directional subsea transducers and a portable surface controller with dunking transducer which enables remote operation from a lifeboat or stand-by support vessel.

The system consists of a rack mounted or portable BOP Command Unit, intelligent Deep Acoustic Remote Transducers (DARTs) programmed to receive, decode and validate acoustic commands, and a Subsea Electronics Module (SEM) that provides the interface to solenoids and read-back sensors. The BOP Command Unit generates acoustic commands in response to operator intervention and transmits them via a simple over-the-side or hull-mounted transducer to the DARTs.

The DARTs are usually located on folding arms which extend outwards when the BOP is lowered from the vessel. This ensures a free path of communications with the surface. Each system has a unique address and its 2 DARTs are programmed to respond only to commands which are specifically addressed to them.

Once decoded and validated, the acoustic commands from the surface are forwarded to the SEM, which in-turn activates solenoid valves which operate the hydraulic rams and close the stack down. Up to 12 function outputs operate the solenoid valves which control the hydraulic operation of BOP Rams.

A single command cycle can be selected which initiates a pre-defined sequence of valve operations, considerably speeding up BOP shut-in and disconnect operations in an emergency.