The US Navy has brought signal lamp ship-to-ship communications into the texting age. In a recent test, the guided-missile destroyer USS Stout flashed a message in fast light bursts across 250 ft (76 m) of water to the guided-missile cruiser USS Monterey tied up at a pier at Naval Station Norfolk, Virginia. It did this using a signal lamp retrofitted with the Flashing Light to Text Converter (FLTC) system, which allows sailors who aren't experts in Morse code to quickly send and receive messages.
The dramatic clack and flash of the signal lamp may seem like some arcane practice only appearing in old war movies and newsreels, but the simple device for sending Morse code messages using a search lamp fitted with shutters is still very much in use by navies all over the world. True, it's a very simple, low-tech system, which is why it's survived for so long.
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In an age of sophisticated digital radio systems that can stream gigabytes of data in a matter of seconds, the signal or Aldis lamp has the advantages of simplicty. It can't be jammed, it can't be tapped into, it works if the main power supply or satellite communications are knocked out, and it can be used for ship-to-ship communications even under the strictest of radio silence conditions.
The problem is that sending messages by signal lamp is slow. Worse, it depends on being proficient in Morse code and that's a problem in a modern world where Morse is almost never used in either naval or civilian circles. This means that lamp operators need to be specially trained and it's very hard to achieve the right speed and accuracy in sending and receiving.
Developed under the sponsorship of the Office of Naval Research's (ONR) TechSolutions program, the FLTC system is designed to overcome these problems in the form of an upgrade package that can be retrofitted to the back of any standard signal lamp.
The system is still in prototype form and consists of either step motors to operate the lamp shutters or LEDs that replace the usual incandescent bulbs, while at the other end a GoPro camera captures Morse code flashes from the other ship. In between sits a proprietary converter in the form of a handheld device or a laptop that runs specialized software algorithms. These convert messages tapped out on the screen into Morse code that is flashed from the lamp, or converts received Morse code falshes back into text messages that are displayed onscreen.
This makes it possible for anyone to send and receive signals without knowing anything about Morse code, while allowing a more traditional signalman to communicate with them without difficulty.
In recent tests, Scott Lowery, an engineer at Naval Surface Warfare Center (NSWC) Panama City, Florida was taken a bit too literally.
"I asked them to text me something random, so they signaled the word 'random," says Lowery. "Simple, but it shows the system is working."
First developed in 2015 by ONR's rapid-response TechSolutions program and Creative MicroSystems Corp, FLTC will be delivered to the Naval Surface and Mine Warfighting Development Center (SMWDC) later this year for testing and evaluation. The hope is that a standard retrofit kit will be issued throughout the US fleet next year.
"The best part of this flashing light converter is how easy it is for Sailors to use," says Lowery. "It's very intuitive because it mirrors the messaging systems used on iPhones. You just type your message and send it with the push of a button."
The video below shows the FLTC system.