Aquatec first launched a subsea communication system in 1997 - the first acoustic AQUAmodem. Since then, we have developed three AQUAmodem technologies that we integrate into custom engineered solutions for subsea monitoring. In addition, we provide advice and assistance on the best communication methods for your project.

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Aquatec offers communication systems based on two data transmission methods – optics and acoustics.

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AQUAmodemop1The AQUAmodem Op2 optical modem was developed for short range communication over 5 years ago. It provides a seamless interface between the user and any subsea instrumentation with RS232 serial interfaces, such as our AQUAlogger oceanographic instruments, HYDROlog hydrotest loggers and LEAKlog leak detection sensors – typically via an ROV umbilical. It is available as a standard product, but can be customised for specific data transfer requirements and applications.

The AQUAmodem Op2 features individual unit addressing and automatic optical or serial data wake-up, to conserve the life of the external battery pack and prolong the service of the device. The instrument permits short range interrogation, commanding, and data download for your subsea monitoring equipment, providing you with a cost-effective and efficient solution to solve your subsea communication needs.



Subsea acoustic data transmission is a powerful tool, improving efficiency, availability of data and reducing the need for underwater intervention. However, the transmission of acoustic signals subsea is complex and dependent on a variety of environmental factors, including water column structure, bubbles and noise. As a result, Aquatec acoustic modems are not available as off the shelf products. Instead, we work with you to ensure communication success with custom made modems for each project.


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AQUAmodem 500

AQUAmodem 500 — Integrated measurement and data acquisition

The AQUAmodem 500 instruments represent a breakthrough in low cost underwater communications. Perfect for long-term, multi-point condition monitoring, the system combines the proven data acquisition capabilities of Aquatec’s AQUAlogger underwater instrumentation with a low-power acoustic transmission system. At the surface is a standard AQUAmodem receiver unit that decodes the data signals transmitted from multiple subsea units.

The modems offer low cost, “send and forget” data transmission that is ideally suited to transmitting very low bandwidth data – often a single data value – at regular intervals. Up to 64 uniquely identified transmitters can be distributed around a given subsea environment. Typical AQUAmodem 500 transmitters include sensors and data acquisition components to suit a particular distributed instrumentation requirement.

Each unit acquires and transmits its data at preset regular intervals, with carefully controlled timing to minimise data collisions. Transmission rate can be made dependent upon the acquired value – for example increasing the data rate in the event of a threshold being exceeded. A single acoustic receiver picks up all the data transmissions and either displays the results or passes them on to other systems via radio, satellite, GSM, or wired digital or analogue methods.


AQUAmodem 1000 configurable modem

The AQUAmodem 1000 is a fully bi-directional communication system, with capability to transmit up to 10 km in its long-range configuration. It is not available as a stand-alone instrument, but provided as a component in custom engineered solutions, and is tailored to customer specific applications to optimise performance.

Aquamodem 1000The modem provides a bi-directional command and data telemetry link, capable of sending and receiving commands, and communicating data over long range and in deep water. This system allows up to 63 uniquely identified transceivers to initiate or receive command and data transmissions.

The transceivers include a substantial data storage capability, so that attached equipment can pass data to them in a ‘store and forward’ mode, for onward transmission when a transmission channel is available. The data can also be recovered later when the modem is retrieved.

With a flexible command and data architecture, including data validation and automatic retransmission requesting, the system can be configured to suit many different commanding, data acquisition and data transmission applications.


Case study: real time pipeline temperature monitoring using the AQUAmodem 500aquamodem case study

This AQUAmodem 500 instrumentation set was developed specifically for a new pipe spool installation in South East Asia, where knowledge of two subsea pipeline temperatures was required in real-time for flow assurance monitoring. Precision temperature sensors integrated into the acoustic transmission module were isolated from the surrounding water by the custom insulated mounting saddles.