The other components of Deep Siren include computers onboard subs and in communications facilities—which may be located ashore, or onboard ships or aircraft—to access messages, along with special software to interpret them. The software—written by RRK—matches different acoustic tones emitted by the buoys with a set of vocabulary words shared between the sender and receiver, performing the translation from words to tones and back to words again. This methodology allows communications to a submarine in a format similar to text messages that occur on a cell phone or PDA.
Deep Siren acoustic technology uses digital message processing to ensure that the receiver can move at a rate of greater than 30 knots (about 35 miles per hour) without incurring any measurable interference. Deep Siren uses digital signaling capabilities at lower frequencies—less than two kilohertz— and permits signal encryption to achieve secure sonar communications at a substantial range to a submarine at depth. Secure and encrypted signals permit more liberal communication from ship to submarine; enemy units may be able to pick up the signals, but they cannot decode them.
The Navy plans to conduct an at-sea military assessment of Deep Siren in June as part of its Communications at Speed and Depth initiatives.