In the face of the continuous development of marine technology and the need to ensure safety and reliable communication for vessels, satellite systems have become an indispensable element of ship equipment. One of the advanced devices used for maritime satellite communication is the LT-3100S GMDSS System, a product of the Danish company Lars Thrane A/S. Designed for open-sea vessels, both commercial and recreational, it is one of the most advanced solutions available in the satellite communication sector.

In this article, we will present what the LT-3100S is, its functions, and how to use them. We will also discuss why this device is superior to the Inmarsat C standard, how it meets regulatory requirements regarding the non-use of printers by allowing data storage, and how its LRIT (Long Range Identification and Tracking) and SSAS (Ship Security Alert System) functions operate.

What is the LT-3100S?

The LT-3100S is a modern satellite communication system that uses the Iridium global network. Thanks to this technology, the device provides full coverage worldwide, including in polar regions, which are often beyond the reach of other technologies. The system is intended for use on all types of vessels, offering support for both standard ship-to-shore communication and emergency situations.

Main Components of the LT-3100

  • LT-3110 Control Unit – responsible for managing the device’s functions and integration with other onboard systems. The control unit is equipped with a display and function buttons that enable full system control.
  • LT-3130 Antenna – ensures satellite communication. It must be mounted outside the vessel, providing a clear view of Iridium satellites. The antenna’s advantage is its distance capability, as the control unit and antenna can be up to 500 meters apart.
  • LT-3120 Handset with LT-3121 Cradle – serves as the main voice interface for the system, enabling conversations. It features volume control buttons and a handset detection function for answering and ending calls.

Main Features of the LT-3100

The LT-3100 offers comprehensive communication capabilities that meet all maritime requirements, including the International Maritime Organization (IMO) regulations and the Safety of Life at Sea (SOLAS) Convention. The system’s main features include:

  • Two-way voice communication – enables crew and passengers to make phone calls to shore or other vessels.
  • SMS messaging – allows sending and receiving text messages, which can be useful for short information exchanges.
  • Data transmission – supports data transfer, providing access to email and report submission.
  • LRIT – the Long Range Identification and Tracking function enables long-distance identification and tracking of vessels.
  • SSAS – the Ship Security Alert System allows the crew to quickly send an emergency alert without requiring voice communication.

How to Make a Phone Call with the LT-3100?

Making a call with the LT-3100 is simple, thanks to its intuitive operation. Here are the steps:

  • Turn on the system – ensure that the LT-3110 control unit is powered on and connected to the satellite (the signal icon is in the upper right corner of the display).
  • Dial the number – use the keypad to enter the phone number (preceded by two zeros and the recipient’s country code, e.g., 0049). You can also select it from the contact list by pressing the MENU button, navigating to the Phone section, selecting Contacts by pressing ENTER, and finding the desired contact.
  • Initiate the call – after entering the number, press the green phone button on the panel to start the call.
  • Have the conversation – when the call connects, you can speak through the handset, adjusting the volume with the “+” and “-” buttons.
  • End the call – to end the conversation, press the red button or place the handset back on the cradle.

How to Add a Contact to the LT-3100 Phone Book?

Adding a contact to the phone book is straightforward. Assigning an email address to a contact also streamlines communication. To complete the phone book:

  • Go to Menu, then the Phone section, select Contacts, and press ENTER.
  • Create a new contact by selecting NEW and entering:
    – Name (recipient’s name) and pressing ENTER
    – Phone (phone number, adding + and country code) and pressing ENTER
    – Email (recipient’s email address) and pressing ENTER
  • Verify the contact details; if all data is correct, press Apply.
    The contact is now saved in the phone book, and you can easily send SMS and email messages.

How to Send an SMS from the LT-3100?

The LT-3100 system supports SMS, useful for sending short text messages. Here’s how:

  • Go to MENU – navigate to the Phone section, select SMS, and press ENTER.
  • Create a new message – select New. Fields for entering the recipient’s number and message content will appear.
  • Enter the recipient’s number – type the phone number or select it from contacts.
  • Compose the message – use the alphanumeric keypad to type the message. Multi-key press mode allows for different letters.
  • Send the message – once the message content and number are entered, select Send to send the SMS.

How to Send an Email Using the LT-3100 Terminal?

Sending an email is as simple as sending an SMS.

  • Go to MENU – navigate to the Phone section, select SMS, and press ENTER.
  • Create a new message – select New and then Contacts.
  • Search for the recipient among saved contacts; when you find them, press Select.
  • Select whether to send the message as SMS or Email.
  • Type the message content and press Send to send it.

How to Run a Terminal Test on the LT-3100?

Regular terminal testing is crucial for connection stability. Lars Thrane has a unique test procedure that is easy to perform:

  • Go to MENU, find the GMDSS section, select Terminal Test, and press ENTER.
  • Select GMDSS Test by pressing Start and follow the on-screen instructions.
  • Lift the cover and hold down the DISTRESS button for 3 seconds.
  • Wait for the Distress Alert and Distress Call test results; if all is well, “Passed” will appear next to the functions.
  • Proceed to the next test by pressing Next and await the MSI test result; if communication succeeds, “Passed” will appear. Press Next again.
  • Final results – if all tests pass, “Passed” will appear three times, indicating the system works correctly. Press Done to end the test.

LRIT (Long Range Identification and Tracking) in the LT-3100

The LRIT (Long Range Identification and Tracking) function enables long-distance identification and tracking of the vessel, as required by IMO conventions for larger commercial vessels. The LT-3100 meets LRIT requirements, automatically transmitting location data to monitoring centers, enhancing safety and allowing easier tracking in international zones.

SSAS (Ship Security Alert System) in the LT-3100

The SSAS (Ship Security Alert System) allows the crew to send a discreet emergency signal in case of threat, such as a piracy attack. This SOLAS-compliant function is easy to activate and ensures immediate notification without voice communication, which is crucial in crisis situations.

Why Doesn’t the LT-3100

Require a Printer?

SOLAS and IMO regulations require ships to have communication and navigation documentation, but they do not specify that this data must be stored in printed form. The LT-3100 allows for digital data storage and archiving, complying with ship documentation regulations and eliminating the need for a printer. In the digital age, this solution is more economical, easier to manage, and resistant to harsh maritime conditions.

The LT-3100’s Advantage over the Inmarsat C System

The LT-3100 surpasses the Inmarsat C system in several ways:

  • Global coverage – the Iridium network covers 100% of the Earth’s surface, including polar regions where Inmarsat C may be unavailable.
  • Two-way voice and SMS communication – the LT-3100 provides full two-way voice and SMS communication, while Inmarsat C mainly supports text services.
  • Lower latency – the LT-3100 operates with lower latency, improving voice call quality.
  • Connection stability via low-orbit satellites – Iridium’s low-orbit satellites ensure more stable connections and continuous connectivity in dynamic conditions.

Summary

The LT-3100 is an advanced satellite communication system combining voice, SMS, data, LRIT, and SSAS functions, offering safe and reliable communication at sea. Its advantages over Inmarsat C and digital data archiving make it ideal for modern vessels. It also meets all safety and communication requirements without needing a printer.

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