The desired actual acoustic data rate can be selected by picking from a set of telemetry schemes. The environmental conditions (SNR) will dictate what telemetry schemes can be used effectively.
Available telemetry schemes
The lower telemetry schemes are most robust whereas the higher schemes make better use of the battery life, allowing more data to be sent with the same amount of power. Supported telemetry schemes include:
• TS0 (100 bits/s)
• TS1 (200 bits/s)
• TS2 (400 bits/s)
• TS3 (900 bits/s)
• TS4 (3000 bits/s)
• TS5 (6000 bits/s)
• TS6 (3500 bits/s)
• TS7 (9000 bits/s)

What is meant by SNR?

SNR is an abbreviation for Signal-to-Noise Ratio and is a measure which describes the ratio of signal power to the noise power. A good signal to noise ratio helps when trying to achieve a reliable acoustic communications link.

What affects SNR?

The following all affect the ratio of signal to noise power:
• The acoustic channel (deep fading caused by reverberant geometries)
• The source level of the transmitting Modem 6
• The gain level used by the receiver electronics
• Electrical noise sources, e.g. noise conducted on the power lines or induced by modulated signals to control thrusters etc.
• Cable length and inadequate shielding of cables