Underwater Acoustic Modem

Transmitting data reliably though water that may be turbid or saturated with unwanted noise is extremely difficult. Acoustics have been proven to be the most reliable method to transmit critical data in this harshest of environments.

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Small size

Small size makes it easy to integrate on any ROV/AUV.

Easy to use

Auto-sync and being fully omnidirectional makes reliable communication easy.

Proprietary protocol

Reduce packet loss and stop worrying about poor data quality.

How the Water Linked modems work:

Operating principle

Transferring data underwater has traditionally required cabled solutions. An underwater wireless modem can allow for two-way-communication without the need for cables. Employing a wireless solution can greatly simplify what were previously considered to be resource heavy tasks.

1. Auto Sync
The modems (3) and (4) are set to the same channel and will auto-sync after a few seconds.

After sync is complete, each modem is given dedicated time slots when it is allowed to transmit and when it shall listen.

2. Transmit / Receive
When a modem receives a payload of data from its host (in this case, an AUV) it will start transmitting this payload in a package structure.

The other modem which is in sync, will receive the transmitted data packages in dedicated time slots.

3. & 4. Modem
Each AUV carries a Modem which is interfaced using a lightweight API.

Auto sync

The Modem has an advanced auto-sync feature which makes it extremely easy to use!

1. Syncing

Two modems configured on the same channel will auto-sync once they are within reach of each other. The auto-sync procedure only takes a few seconds!

Synced modems are ready to operate the two-way communication link.

2. Out of reach

If the two modems get out of reach of each other, they will automatically enter search-mode. During search mode, they will not transmit payload packages.

3. Re-Syncing

When the modems get back into reach of each other, they will automatically sync up again and be ready to transmit payload packages!


The Water Linked Modem is fully omnidirectional!

Omnidirectional means that the modems can be turned around all axes and still maintain its robust data link. This is especially important for ROV/AUV applications where the modems are in constant motion.

Water Linked Acoustic Modem vs legacy products

When the first subsea acoustic modems came to the market (and actually still), the manufacturers designed their modems as simple “pingers” where the digital information was encoded as frequency A for “1” and frequency B for “0”. The receiving modem would pick up these frequencies and feed 0’s and 1’s to the receiving computer. This method is extremely vulnerable to packet loss and other interference and the result was that very often the information received was corrupt.

The Water Linked Modem takes a completely different approach. It uses an advanced proprietary protocol where a significant portion of the gross available data rate in the wireless link is used to enclose the information with error correction features. Customers can therefore put confidence in the data link. In many applications, it is a valuable feature that you can actually trust that the information received is correct.

Available products

Modem M64

Explore our two-way, 64bps acoustic modem, the M64.

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