The S2C 7/17 is a long-distance underwater acoustic communicator produced by Germany's Evologics, which USES a range of new technologies to improve communication reliability and be able to measure relative speed and distance.
Working depth: up to 6000m
Action distance: 8000m
Working frequency: 7-17khz
Data transmission rate: 6.9kbit/s
Bit error rate: 10-10
There are other types of S2C products: s2c12/24, s2c18/34, s2c48/78, and s2c40/80 to suit different depths and distances.