Fast mid-range communication and positioning - all-around performer for deep-water operations


PRO 18/34 deep
The PRO 18/34 deep modem delivers full-duplex underwater communication and simultaneous positioning with our field-proven S2C acoustic technology. This depth-rated 18/34 version achieves up to 13.9 kbit/s over 2000 m, ensuring stable performance for deep-water operations.
PRO 18/34 deep
18/34 deep is the version of 18/34 in Titanium housing, depth-rated to 6000 m - ideal for deep-sea operations that require fast connections between devices at similar depths.
[01]
Versatile all-around performer
With their balance of speed, range, and directivity, 18/34 deep models are a great choice for mid-range deep water operations, and can be combined with 18/34 and 18/34 hemi for extended acoustic coverage
[02]
Maximum flexibility and interoperability
Full-fledged PRO modem inside, offering the widest selection of configuration options and add-ons - including the JANUS option, enabling interoperability with third-party acoustic devices
[03]
Communication and positioning in one
Pair with other 18/34 devices for USBL, LBL or hybrid positioning and simultaneous data transfers - no mode switching needed
PRO 18/34 deep
Speed Range
Fast short- and mid-range devices
Range
Mid-range
Transducer Beam Pattern
horizontally omnidirectional
Frequency Band
18 - 34 kHz
Acoustic Connection
up to 13.9 kbit/s
Listed bitrate refers to performance in optimal acoustic conditions and varies with the environment.
Operating Range Revision Notice
We have corrected the operating range listing for this model. The previously stated operating range of 3500 m reflects performance under near-ideal signal propagation and processing conditions. In typical field applications, a realistic average operating range of approximately 2000 m can be expected.
Delrin Housing
Stainless Steel Housing
Titanium Housing
6000 m
OEM Build Transducer
6000 m
Bit Error Rate
less than 10
-10
Internal Data Buffer
1 MB, configurable
Host Interface
Ethernet or RS-232
Interface Connector
up to 4 connectors, Ethernet and serial combinations
The RS-232 Interface can be replaced with a RS-422 interface upon request.
Slant Range Precision
0.01 m
USBL Bearing Accuracy
USBL Nominal SNR
Slant range accuracy depends on the availability and accuracy of the sound velocity profile.
Power Consumption | Stand-by Mode
2.5 mW
Power Consumption | Listen Mode
5 - 285 mW
Power Consumption | Receive Mode
0.8 W
Max. Output Power
up to 65 W
Max. Transmit Source Level (dB re 1 µPa @ 1 m)
185
The transmit source level is adjustable in 4 levels. Listed values correspond to a device with 24 VDC nominal input voltage. Source level and achievable range are lower for other power supply options.
User-configurable Listen Mode is only available with a Wake-Up module installed. Power consumption in Listen Mode depends on the Listen Mode settings.
Listed power consumption values correspond to a device with RS-232 interface. Add 500 mW if an Ethernet interface is installed. Add 300 mW if the Wake-Up Module is installed.
Power Supply Options | External
24 VDC or 12 VDC
Power Supply Options | Internal Battery
Rechargeable NiMH or Li-ion battery, up to 342.8 Wh
Various battery capacities and charger options available for devices with internal batteries.
Housing Dimensions
Ø 113x196 mm
Total Length
303 mm
USBL Antenna Dimensions
Weight, dry/wet
6500/4500 g
Reference dimensions and weight of a build in Delrin housing without an internal battery. Other builds are larger and heavier, depending on the selected housing, configuration, and add-on options.
Naming and compatibility notice
Before mid-2025, this model was offered as S2C R 18/34D. Our product naming has been streamlined for consistency - the PRO 18/34 deep modems are acoustically compatible with all existing S2C 18/34 devices.
Acoustic Performance Factors
Please note, that listed bitrate and operating range values refer to performance under optimal acoustic conditions and may vary with the environment. These figures indicate the upper limits of modem performance rather than guaranteed real-world results. Acoustic performance - including achievable range and data rate - depends on both environmental factors and the installation setup. It can be influenced by multipath propagation, variations in the sound velocity profile, ambient noise levels, and interference from vessel systems or nearby machinery. Optimal conditions typically include a calm sea state, low background noise, a uniform sound velocity profile, line-of-sight geometry, minimal multipath, and proper transducer placement.
Specifications are subject to change without notice.
PRO 18/34 deep
Category
Build type
Technical Details and Options
Rather than being integrated directly into the housing, the transducer connects to the modem unit with a cable. This allows for flexible placement of the transducer on the carrier structure, ensuring unobstructed signal transmissions away from sources of noise.
Technical Details and Options
Integrations with UUV platforms, sensor stations, infrastructure
Series Compatibility
PRO, PRO USBL, MINI, TINY
Category
Build type
Technical Details and Options
A housing-free modem build with separate electronics and a cable-mounted transducer, designed for seamless integration into third-party systems and custom platforms.
Technical Details and Options
Integrations with UUV platforms, sensor stations
Series Compatibility
PRO, PRO USBL, MINI, TINY
Category
Positioning
Technical Details and Options
Measures water pressure to provide accurate depth information for improved positioning accuracy or georeferencing sensor data.
Technical Details and Options
Positioning and navigation of UUVs, georeferencing sensor data from subsea instruments
Series Compatibility
PRO, PRO USBL
Category
Power management
Technical Details and Options
Enables power-saving sleep mode: the low-power Wake-Up Module turns on the modem when incoming acoustic signals or data interface input are detected. After data transmission or reception, the modem powers down automatically to save power. The acoustic channel is monitored periodically, with adjustable cycle settings to optimize power management.
Technical Details and Options
Power saving for long-term deployments, integrations with low-power platforms
Series Compatibility
PRO, PRO USBL, MINI, TINY
Category
Power management, External instrument control
Technical Details and Options
Provides power supply to up to three external instruments, allowing them to be switched on or off with commands to the modem. Enables remote control and efficient power routing to connected devices.
Technical Details and Options
Power management and remote control for external sensors and instruments
Series Compatibility
PRO, PRO USBL
Category
Release and recovery
Technical Details and Options
Reliable release mechanism for recovering underwater assets to the surface is activated with an acoustic command to release an anchor or other mooring. Also available as a cable-mounted OEM version for system integration.
Technical Details and Options
Automated recovery of submerged assets to the surface - seafloor sensor stations, postioning nodes
Series Compatibility
PRO, PRO USBL
Category
External instrument control
Technical Details and Options
A built-in optocoupler enables transmitting a software configurable (under special request) trigger electric pulse to external instruments, activating action with an acoustic command to the modem.
Technical Details and Options
Remote activation of external equipment such as sensors, instruments, actuators, lights, cameras
Series Compatibility
PRO, PRO USBL
Category
Research and development, Positioning
Technical Details and Options
Enables highly precise timekeeping of the modem to prevent its internal clock from drifting. Accepts 1 PPS input from an external GNSS and optionally includes a CSAC (Chip Scale Atomic Clock) or OCXO (Oven Controlled Crystal Oscillator) clock for stable, accurate timekeeping required for synchronized operation of modems.
Technical Details and Options
Applications requiring precise time synchronization between modems: enhanced LBL performance, custom positioning solutions, research and development of underwater networking protocols.
Series Compatibility
PRO, PRO USBL, MINI, TINY
Category
Research and development
Technical Details and Options
Software Defined Modem (SDM) mode is a firmware add-on that allows the modem to transmit user-defined acoustic waveforms, trigger reception with a customizable reference signal, and receive the incoming waveforms. SDM functionality complements the standard S2C communication protocol without affecting the modem’s base capabilities.
Technical Details and Options
R&D on signal modulation and communication protocol standardization
Series Compatibility
PRO, PRO USBL, MINI, TINY
Category
Interoperability
Technical Details and Options
Enables interoperability with third-party acoustic devices over the standardized JANUS (NATO ANEP-87) communication protocol. Available for selected models, JANUS functionality complements the standard S2C communication protocol without affecting the modem’s base capabilities.
Technical Details and Options
Ad-hoc subsea networks with third-party devices, mixed-vendor joint operations where open communication standards are required.
Series Compatibility
PRO - selected models
Category
Research and development
Technical Details and Options
Open developer environment (sandbox) built into the modem, allowing custom software to run directly onboard while maintaining full modem functionality. Provides a container for integration of user applications.
Technical Details and Options
Development of custom applications for underwater acoustic modems, testing and embedding custom software on actual modem hardware.
Series Compatibility
PRO, PRO USBL, MINI, TINY
Category
Positioning
Technical Details and Options
Upgrades a PRO modem into a PRO USBL device. The USBL antenna includes extra hydrophones for accurate underwater positioning alongside the main modem transducer.
Technical Details and Options
Enables real-time USBL tracking of underwater assets - as topside or bottom side reference unit for USBL positioning
Series Compatibility
PRO
PRO 18/34 deep
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