Surface Deployed Acoustic Modem 6

What you need to know

Transfers data at up to 9,000 bps
Support long range communications; up to 11 kilomteres
Highly reliably; built around our Wideband^®2 acoustic and 6G^® hardware platform
Options for buoys, unmanned surface vehicles and ships

Modem 6 acoustic modems are designed to wirelessly transfer sensor data from subsea 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 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.

MODEM 6 – ACOUSTIC MODEM

We offer sub-surface, OEM (no housing) and surface-deployed 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.

Surface Deployed Acoustic Modem 6 Options

Pairs of matching Modems 6 instrument can be used to send and receive your data. However we also offer a range of dedicated surface-deployed modems which can be installed permanently through the hull of your survey vessel, over-the-side of a vessel of opportunity or in the payload of an unmanned surface platform. These are optimised for maximum physical protection, communication range and support the highest data telemetry transfer rates.

Modem 6 Transceiver
Offers ultimate performance. Excellent vessel noise rejection and multiple receivers ensure the highest data rates possible. Can be upgraded to a Ranger 2 USBL transceiver • Proven 11 km+ range capable

• Optimised for noisy environments
• Ideal for permanent vessel fit
• Surface system kit: SIU, cable drum, cage

Modem 6 Dunker
Available in MF and LMF, omni and directional, the Modem 6 Dunker is a rugged easy-to-mount instrument designed for excellent horizontal and shallow water communication

• Up to 9000 bps true user data rate
• Shock mounted electronics
• MF/LMF omni or directional transducers
• Rugged, easy to mount housing

Modem 6 Mini-Dunker
If you’re using a pair of Minis, this accessory kit turns one of them into a lightweight dunker with protection from knocks and bumps during deployment and recovery

• Perfect for small vessels
• RS485 comms interface
• Surface system kit: SIU, cable and side protection

More about this product

Surface Deployed Acoustic Modem 6 Specifications & DataSheet

Modem 6 Transceiver

Feature	Modem 6 Transceiver 8182-0001	Modem 6 Transceiver 8193-0012
Operating Frequency	MF (21–32.5 kHz)	LMF (14–19 kHz)
Operating Range	Up to 7,000 metres	Up to 12,000 metres
Acoustic Coverage	Up to ± 90º	Up to ± 90º Optimised for deep water (depending on frequency of operation)
Transmit Source Level re 1 uPa @ 1 m	200 dB	200 dB
Tone Equivalent Energy (TEE)*	206 dB (13 JA)	206 dB (13 JA)
Transceiver 6 Operating Voltage	48 V dc (±10%), typical 15 W, max 120 W – supplied by the SIU
SIU Operating Voltage	90–260 V ac, 50/60 Hz, 200 VA max – power out 48 V dc, 2.0 A max
Communications	Primary and secondary port: RS485 (half-duplex) SIU input: RS232	Primary and secondary port: RS485 (half-duplex) SIU input: RS232
Operating Temperature	-5 to 40ºC
Storage Temperature	-20 to 45ºC
Mechanical Construction	Aluminium bronze
Dimensions; Height x Diameter	373 x 225 mm	455 x 310 mm
Weight in Air /Water**	28/15 kg	41/20 kg

Surface System Kit	Sonardyne Part Number
Surface Interface Unit (SIU)	620-7079
Cable Drum (100 m)	641-3614
Deck Cable (5 m)	820-0127
Dunker Cage	641-3612

*TEE – WBv2+ signals are 4x the duration of Sonardyne tone signals (WBv1 & WBv2 are 2x). The TEE figure shows the operational performance when comparing wideband and tone systems.
Detection performance is directly related to the signal energy (Joules (Watt seconds)) and not power. WBv2+ signals are longer in duration (greater energy) than WBv1 and Tone, therefore the detection performance is the same or improved for low transmit source levels.

**Estimated Weights.

Modem 6 Dunker

Feature	Modem 6 Dunker Type 8307-1351	Modem 6 Dunker Type 8307-1353	Modem 6 Dunker Type 8307-1355	Modem 6 Dunker Type 8307-1356
Depth Rating	1,000 metres	1,000 metres	1,000 metres	1,000 metres
Operating Frequency	MF (21–32.5 kHz)	MF (21–32.5 kHz)	LMF (14–19 kHz)	LMF (14–19 kHz)
Transducer Beam Shape	Omni-directional	Directional	Omni-directional	Directional
Transmit Source Level (dB re 1 µPa @ 1 m)	187–197 dB (4 levels)	190–202 dB (4 levels)	187–197 dB (4 levels)	190–202 dB (4 levels)
Tone Equivalent Energy (TEE*)	193–202 dB	196–208 dB	193–202 dB	196–208 dB
Receive Sensitivity (dB re 1 µPa)	90–120 dB (7 levels)	80–120 dB (7 levels)	90–120 dB (7 levels)	80–120 dB (7 levels)
Range Precision	Better than 15 mm
Serial Comunications	Primary and secondary port: RS485 (half duplex) SIU input: RS232
Dunker 6 Operating Voltage	24 or 48 V dc (±10%) – supplied by the SIU
SIU Operating Voltage	90–260 V ac, 50/60 Hz, 200 VA max – power out 48 V dc, 2.0 A max
External Power Active (listening) Peak (transmission)	<3 W typical (max 6W when charging) <80 W
Battery Life – Li-ion (Listening)	3 days
Mechanical Construction	Super-duplex stainless steel
Dimensions; Length x Diameter	692 x 200 mm	660 x 200 mm	586 x 200 mm	641 x 230 mm
Weight in Air/Water**	24/16 kg	26/17 kg	20/14 kg	28/17 kg
Connector Type	AGP (8-way female)

*TEE – WBv2+ signals are 4x the duration (WBv1 & WBv2 are twice) of Sonardyne tone signals, therefore the TEE figure is to give the user an idea of the operational performance when comparing Wideband and Tone systems.

** Estimated weights

Modem 6 Mini-Dunker

Feature		Modem 6 Mini-Dunker 8244-3151
Depth Rating		3,000 m
Operating Frequency		MF (21–32.5 kHz)
Transducer Beam Shape		Omni-directional
Source Level (re 1 µPa @ 1 m)	High Power	187 dB
	Low Power	181 dB
Tone Equivalent Energy (TEE)* WBv2+	High Power	193 dB
	Low Power	187 dB
Range Precision		Better than 15 mm
Depth Sensor		± 0.5% full scale
Serial Communications		Primary and secondary port: RS485 (half-duplex) SIU input: RS232
Modem Mini Dunker 6 Operating Voltage		24 or 48 V dc (± 10%) – supplied by the SIU
SIU Operating Voltage		90–260 V ac, 50/60 Hz, 200 VA max – power out 48 V dc, 2.0 A max
External Power Consumption	Sleep	<300 mW
	Wideband Listening	<500 mW
	Battery Charging	6 W
	Peak (Transmission)	<50 W
External Power Switch		Yes
Battery Life (li-ion 15 V)	Listening	30 Days
Operating Temperature		-5 to 40ºC
Storage Temperature		-20 to 55ºC
Mechanical Construction		Anodised aluminium alloy and plastics
Dimensions: Diameter x Length		98 mm x 499 mm
Weights in Air/Water**		5.1/2.2 kg

Surface System Kit
Surface Interface Unit (SIU)		620-7079
Deck Cable (20 m)		820-0834

**Estimated weights

FAQs

What Modem 6 product best suits my application?

The Modem 6 family describes a range of underwater acoustic modems designed to transfer data acoustically at speeds from 200 bps through to 9,000 bps. All of the Modem 6 products utilise the same acoustic and serial protocol allowing a mix-and-match approach to suit a wide range of operating scenarios. The smaller Modems (Sub-Mini and the Mini) are suitable for vehicles and are both fitted with smaller rechargeable batteries. The standard Modem 6 is significantly larger but boasts increased transmission power and is suited to powering external equipment for long duration deployments. RS232 or RS485 (half-duplex) options are available.

How much latency is to be expected?

The latency is governed by:

The through-water travel time which is governed by the distance divided by the sound speed
The duration of the telemetry which is governed by the amount of data being sent and the selected telemetry scheme

Is there a handshaking mechanism or other link establishing sequence?

The Modem 6 doesn’t use any initial handshaking or establishing sequence as the power levels, gain and telemetry scheme are configured ahead of time. There is a small header (10 bytes) appended to each packet that is used internally by the Modem to transfer acknowledgement and status information.

How do I select the optimal telemetry scheme?

The optimal data rate is usually considered to be the fastest telemetry scheme that works robustly. Whether a telemetry scheme works reliably is dependent on the acoustic channel and the received SNR. Modem 6 telemetry is quantised in to blocks of approximately 240 milliseconds, hence for small payloads there can be no benefit in faster telemetry schemes once the payload fits in to a single block of telemetry.

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

How does the MDFT protocol work?

A modem data frame transfer is the name given to a set of acoustic transactions that provide bidirectional transfer of data between two Modem 6 units. The transfer provides guaranteed data delivery and always ensures that any downlink data is delivered prior to the uplink data being sent (to allow the remote Modem 6 the chance to extract the payload serially and respond).

What is meant by "transparent mode"?

Transparent mode describes the configuration of a Modem 6 in to a mode whereby it buffers data received on its COM port and automatically begins MDFT acoustics to transfer the data to the configured destination Modem 6. The advantage of transparent mode is that is requires no additional interfacing, the disadvantage is that no Modem 6 diagnostics can be collected to help determine if the acoustic link is optimal and to help diagnose any acoustic issues.

What is the maximum MDFT frame size?

The maximum frame size (denoted here in terms of user payload) depends on the selected telemetry scheme.

TS1 has a maximum frame size of 1,376 bytes
TS2 has a maximum frame size of 2,656 bytes
TS3 has a maximum frame size of 5,728 bytes
TS4 has a maximum frame size of 27,488 bytes
TS5 has a maximum frame size of 55,136 bytes
TS6 has a maximum frame size of 30,048 bytes
TS7 has a maximum frame size of 83,808 bytes

What if my payload is more than the maximum MDFT frame size?

In transparent mode the Modem 6 will continue to transfer the remaining data as long as the previous frame was successfully transferred. In non-transparent mode the MDFT command reply will indicate that more data is available and another MDFT transfer can be scheduled to collect the remaining data.

Does Modem 6 support the MODBUS protocol?

No, there is no official support or testing for MODBUS although the Modem 6 supports binary data and will likely frame MODBUS messages correctly.

Does the Modem 6 support multiple modems rather than a single point-to-point link?

In fully transparent mode, the Modem 6 units are configured to talk to an explicit acoustic address and this precludes using them in multiple modem mode. If a Modem 6 is being interfaced using the MDFT command protocol then it can send and receive data from multiple modems as long as the modem transfers are separated in time (i.e. simultaneous broadcasting of messages is not supported).

What if I still have unanswered questions?

Please contact our dedicated support email: support@sonardyne.com

How many topside Modems do I need?

A single topside modem can communicate individually with over 100 subsea modems, limited only by the number of unique acoustic addresses available.

Sonardyne recommends the Modem 6 Transceiver (Type 8182 & 8193) as a topside unit because it provides the most robust connection through a combination of increased SNR and superior processing gains.

Surface Deployed Acoustic Modem 6

What you need to know

Information Request

MODEM 6 – ACOUSTIC MODEM

Surface Deployed Acoustic Modem 6 Options

More about this product

Surface Deployed Acoustic Modem 6 Specifications & DataSheet

Modem 6 Transceiver

Modem 6 Dunker

Modem 6 Mini-Dunker

FAQs

What Modem 6 product best suits my application?

How much latency is to be expected?

Is there a handshaking mechanism or other link establishing sequence?

How do I select the optimal telemetry scheme?

What is meant by SNR?

What affects SNR?

How does the MDFT protocol work?

What is meant by "transparent mode"?

What is the maximum MDFT frame size?

What if my payload is more than the maximum MDFT frame size?

Does Modem 6 support the MODBUS protocol?

Does the Modem 6 support multiple modems rather than a single point-to-point link?

What if I still have unanswered questions?

How many topside Modems do I need?

Related products

Surface Deployed Acoustic Modem 6

What you need to know

Information Request

MODEM 6 – ACOUSTIC MODEM

Surface Deployed Acoustic Modem 6 Options

Stories about this product

More about this product

Surface Deployed Acoustic Modem 6 Specifications & DataSheet

Modem 6 Transceiver

Modem 6 Dunker

Modem 6 Mini-Dunker

FAQs

What Modem 6 product best suits my application?

How much latency is to be expected?

Is there a handshaking mechanism or other link establishing sequence?

How do I select the optimal telemetry scheme?

What is meant by SNR?

What affects SNR?

How does the MDFT protocol work?

What is meant by "transparent mode"?

What is the maximum MDFT frame size?

What if my payload is more than the maximum MDFT frame size?

Does Modem 6 support the MODBUS protocol?

Does the Modem 6 support multiple modems rather than a single point-to-point link?

What if I still have unanswered questions?

How many topside Modems do I need?

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