Underwater Acoustic modem 6

Modem 6 underwater acoustic modems are designed to wirelessly transfer sensor data from under the water to the surface at speeds between 200 and 9,000 bps.


Built around our field-proven 6G hardware and Wideband 2 acoustic signal platforms, the technology found inside each underwater acoustic Modem 6 instrument has safely transferred many gigabytes of clients’ data so whatever your application, and whatever the water depth, you can be assured of reliable communications performance.

We offer sub-surface, OEM (no housing) and surface-deployed acoustic modems to suit any operational deployment scenario and data transfer mission. You can mount them on seafloor instruments, in an AUV, suspended from a surface buoy or in the hull of an unmanned surface vehicle, and leave them for days, months or years. Uniquely, Modem 6 instruments can be upgraded to offer positioning and navigation capability (e.g. LBL and USBL positioning) if your operational needs become more complex.

Our family of sub-surface Modem 6 instruments benefit from same mechanics and electronics you’ll find in our range of USBL and LBL positioning transponders. These are trusted by leading offshore energy, ocean science and naval customers to perform in the most demanding marine environments, shallow or deep, and all operational scenarios. They are easy to install and all come with a battery pack if external power is not available.

Sub-Mini Underwater Acoustic Modem 6 Modem 6 Sub-Mini
Available in 1,000 metre depth rated housing. Offers excellent horizontal, shallow and deep performance. Internal rechargeable battery provides up to 35 days standby.
• MF omni
• On/Off switch for storage
• 24 V dc external power input
• Advanced transmitter power control
Modem 6 Mini
Available in 3,000 metre depth rated housing. With its integrated li-ion battery and isolated external power supply, Mini is most suitable for vehicles.
• MF and LMF transducers
• RS232/485 serial interface
• 24/48 V dc isolated external power input
• External IO control
• OEM option
Modem 6 Standard 
Similar to a Modem 6 Midi but with larger battery pack options enables deployment for years or even decades. Alkaline and lithium battery options. Optional acoustic release for recovery. Wide range of housing materials available. • High energy 100 Ahr battery pack
• MF/LMF omni or directional transducers
• External power input and output
• 3,000/5,000/7,000 metre housings

Technical information

Feature Modem 6 Sub-Mini 8377-1111
Depth Rating 1,000 metres
Operational Frequency MF (21–32.5 kHz)
Transceiver Beam shape Omni-directional
Maximum Data Rate 9000 bps
Serial Port (RS232) 2400–115200 baud
Data Buffer/Storage 512 kB
Range* 1–2 km
Transmit Source Level (dB re. 1 µPa @ 1 m)
(External Power)
187 dB
184 dB
Receive Sensitivity (dB re 1 μPa) <85 dB
Power Supply Rechargeable NiMH battery or external 24 V
Battery charge 0-100 % 5 hours
Quiescent Life (Battery) >35 Days
Connector 5-Way (Standard) Subconn MCBH5M
Mechanical Construction Aluminium alloy, anodised
Operating Temperature -5 to 40ºC
Storage Temperature -20 to 55ºC
Dimensions (Length x Diameter) 426 x 79 mm
Weight in Air/Water 3.2/1.3 kg
Battery Charger 8370-011-01
Pin Description
1 RS232 comms In (RX)
2 0 V
3 RS232 comms Out (TX)
4 External power 24 V
5 N/A





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