DOCSLIB.ORG

Morse Code and the Information Age Morse Code, Invented by Samuel F. B. Morse in the 1830S, Is a Method of Transmitting Textual

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Morse Code and the Information Age Morse Code, Invented by Samuel F. B. Morse in the 1830S, Is a Method of Transmitting Textual Morse Code and the Information Age Morse code, invented by Samuel F. B. Morse in the 1830s, is a method of transmitting textual information as a series of on-off tones, lights, or clicks that can be directly understood by a skilled listener or observer without special equipment. The International Morse Code encodes the Roman alphabet, the Arabic numerals and a small set of punctuation and procedural signals. The original telegraph system had an apparatus on the receiving end that spat out a string of paper with indentations on it. Short indentations were called “dots” or “dits,” and the longer ones “dashes” or “dahs.” Because many non-English natural languages use more than the 26 Roman letters, extensions to the Morse alphabet exist for those languages. Morse code has been in use for more than 160 years—longer than any other electrical coding system. What is called Morse code today is actually somewhat different from what was originally developed. The Modern International Morse code, or continental code, was created by Friedrich Clemens Gerke in 1848 and initially used for telegraphy between Hamburg and Cuxhaven in Germany. Gerke changed nearly half of the alphabet and all of the numerals resulting substantially in the modern form of the code. After some minor changes, International Morse Code was standardized at the International Telegraphy Congress in 1865 in Paris, and was later made the standard by the International Telecommunication Union (ITU). Samuel Morse's original code specification, largely limited to use in the United States and Canada, became known as American Morse code or railroad code. Aviation In aviation, instrument pilots use radio navigation aids. To ensure that the stations the pilots are using are serviceable, the stations all transmit a short set of identification letters (usually a two-to-five-letter version of the station name) in Morse code. Station identification letters are shown on air navigation charts. For example, Manchester Airport in England is abbreviated as "MCT", and MCT in Morse code is transmitted on its radio frequency. In some countries, if a station begins malfunctioning it broadcasts "TST" (for "TEST"), which tells pilots and navigators that the station is unreliable. In Canada, the identification is removed entirely to signify the navigation aid is not to be used. Radio The original radio operators used Morse code exclusively, since voice-capable radio transmitters did not become commonly available until around 1920. They use a paddle, when pressed to the right by the thumb, it generates a series of dits, the length and timing of which are controlled by a sliding weight toward the rear of the unit. When pressed to the left by the knuckle of the index finger, the paddle generates a single dah, the length of which is controlled by the operator. Multiple dahs require multiple presses. Left-handed operators use a key built as a mirror image of this one. The Navy Radio navigation aids were used for aeronautical broadcasts identify information in the form of Morse Code. Warships, including those of the U.S. Navy, have long used signal lamps to exchange messages in Morse code. Modern use continues, in part, as a way to communicate while maintaining radio silence. Submarine periscopes include a signal lamp. Globally International Morse code today is most popular among amateur radio operators, where it is used as the pattern to key a transmitter on and off in the radio communications mode commonly referred to as "continuous wave" or "CW" to distinguish it from spark transmissions, not because the transmission was continuous. Other keying methods are available in radio telegraphy, such as frequency shift keying. Morse Code as an Assistive Technology Morse code has been employed as an assistive technology, helping people with a variety of disabilities to communicate. Morse code can be sent by persons with severe motion disabilities, as long as they have some minimal motor control. Morse code can be translated by computer and used in a speaking communication aid. An important advantage of Morse code over row column scanning is that, once learned, it does not require looking at a display. Also, it appears faster than scanning. People with severe motion disabilities in addition to sensory disabilities (e.g. people who are also deaf or blind) can receive Morse code through a skin buzzer. Keywords The relatively limited speed at which Morse code can be sent led to the development of an extensive number of abbreviations to speed communication. Perhaps the most famous word in Morse Code is SOS. It was chosen as the international Morse code distress signal, because the three dots for S and the three dashes for O make a clear and distinct signal. Before SOS became the standard radio distress signal, there were others. CQ, interpreted as “seek you,” meaning I'd like to converse with anyone who can hear my signal, was a general call to any station. D was internationally recognized in telegraph cable traffic to precede urgent messages, thus CQD (-.-. --.- -..) meant “urgent message to any station.” OM (old man), YL (young lady) and XYL ("ex-YL" — wife) are also common abbreviations. YL or OM are used by operators when referring to the other operator, XYL or OM are used by operators when referring to his or her spouse. QTH is "location," "my QTH" is "my location." The use of abbreviations for common terms permits conversation even when the operators speak different languages. At the First Congress of Wireless Telegraphy in 1903, the Italians suggested SSSDDD (... ... ... -.. -.. -..) to combine the distinct three dots of the S with the urgency of the D. German radio operators used SOE (... --- .) but quickly realized that the single dot of the E could get easily lost in the static noise. For that reason they had already shifted to SOS by the time of its adoption at the International Radio Telegraphic Convention of 1906. The United States did not adopt SOS until after the Titanic disaster in 1912. A handful Nokia engineers used morse code as their standard alert tone when short message service (SMS) messages were received, of course the morse code reads SMS.This was implemented by them circa 1985. In 1995, the United States Coast Guard ended the use of Morse Code transmissions in its maritime communications service, signalling the end of an era in the history of communications. How is Morse Code Used Today? Communication today relies upon satellites, a complex grid and advanced technology to speed messages rapidly World-wide. The internet has increased information flow and ease of contact in almost unimaginable ways. However, old technology has a way of creeping back, since it is simple, relatively inexpensive and does not depend on the fragile grid systems of modern technology. Morse code operators stand ready to help in dire emergencies, grid failures, or war! Amateur radio operators use Morse code extensively for contests, during which rapid connections are imperative. Morse code only requires a small footprint and therefore is readable when pileups occur on radio bands. The larger the amount of data to be transferred, the larger the amount of bandwidth required. Radios can be constructed cheaply without modulation and run much less power than with more sophisticated equipment. Navigation beacons help airline pilots find and maintain proper headings even today. Flashing light Morse code even from a flashlight may be read several miles away for a lost sailor or hunter. Countless snowstorm rescues have been recorded by stranded drivers flashing an SOS signal on a flashing light. Mirrors accomplish the same thing during the day. The user directs a mirrored sun reflection and then blocks it with his other hand or piece of cardboard flashing out the Morse code signal. Medical uses allow the severely handicapped person to tap or blink out a message that can now be ready by computers, giving new hope and meaning to life for sufferers. A new method for using Morse code involves cell phones and text messages entered from an iambic keyer on the cell phone face. It seems that experienced Morse code operators can enter the text much faster than a QUERTY keyboard operator and can do it without looking at the keyboard. Who knows how brilliant minds will conceive of ways to use this simple technology in the future. In the mean time, knowing code might just allow you to survive, especially in times of catastrophe or national emergency. Timeline 1836 Samuel Morse invents electric telegraph able to send messages up to 500 yards! 1842 Morse builds circuit between Washington DC and Baltimore, 38 miles long but few interested 1844 Morse sends “What God hath wrought” to Capitol 1845 Forms the “Magnetic Telegraph Company” 1847 Received patent for electric telegraph 1847 Patent contested; built telegraph in Europe instead. Paid $80,000; Netherlands to Turkey. 1851 New York Telegraph Co. formed; lines from New York City to Boston & St. Louis. 1851 Western Union formed, based on Morse's success in Europe 1852 Dozens of other local companies formed but very limited due to no “long lines.” 1853 Invention upheld by U.S. Supreme Court. 1854 Samuel Morse returns to United States. 1856 New York Telegraph Co. buys up most of the local companies; renamed Western Union. 1861 Western Union completes lines from Omaha to Sacramento – coast-to-coast. 1861 Telegraph/Western Union become huge assets to Union Army during Civil War. 1865 Western Union enters agreement with the railroads to share lines. 1869 Transcontinental Railroad completed. 1872 Samuel Morse dies, at the age of 80 years old. 1940s Morse code replaced by teletype for most news services and messaging, except maritime. 1970s Morse code eliminated by the railroads.
Load more

Recommended publications
  • Global Maritime Distress and Safety System (GMDSS) Handbook 2018 I CONTENTS
    FOREWORD This handbook has been produced by the Australian Maritime Safety Authority (AMSA), and is intended for use on ships that are: • compulsorily equipped with GMDSS radiocommunication installations in accordance with the requirements of the International Convention for the Safety of Life at Sea Convention 1974 (SOLAS) and Commonwealth or State government marine legislation • voluntarily equipped with GMDSS radiocommunication installations. It is the recommended textbook for candidates wishing to qualify for the Australian GMDSS General Operator’s Certificate of Proficiency. This handbook replaces the tenth edition of the GMDSS Handbook published in September 2013, and has been amended to reflect: • changes to regulations adopted by the International Telecommunication Union (ITU) World Radiocommunications Conference (2015) • changes to Inmarsat services • an updated AMSA distress beacon registration form • changes to various ITU Recommendations • changes to the publications published by the ITU • developments in Man Overboard (MOB) devices • clarification of GMDSS radio log procedures • general editorial updating and improvements. Procedures outlined in the handbook are based on the ITU Radio Regulations, on radio procedures used by Australian Maritime Communications Stations and Satellite Earth Stations in the Inmarsat network. Careful observance of the procedures covered by this handbook is essential for the efficient exchange of communications in the marine radiocommunication service, particularly where safety of life at sea is concerned. Special attention should be given to those sections dealing with distress, urgency, and safety. Operators of radiocommunications equipment on vessels not equipped with GMDSS installations should refer to the Marine Radio Operators Handbook published by the Australian Maritime College, Launceston, Tasmania, Australia. No provision of this handbook or the ITU Radio Regulations prevents the use, by a ship in distress, of any means at its disposal to attract attention, make known its position and obtain help.
    [Show full text]
  • SOUNDS of MORSE CODE (Version 2) NUMERALS (10)
    SOUNDS OF MORSE CODE (Version 2) NUMERALS (10) Using dots and dashes to represent the sounds of 1 di-DAH-DAH-DAH-DAH Morse code is HIGHLY discouraged. 2 di-di-DAH-DAH-DAH Morse code is a language of SOUND, and by 3 di-di-di-DAH-DAH converting SOUND into dots and dashes, THEN 4 di-di-di-di-DAH converting dots and dashes into the letter the 5 di-di-di-di-dit SOUND represents WILL shoot you in the foot when you try to pick up speed. You can count on it. 6 DAH-di-di-di-dit (Continued next page...) 7 DAH- DAH-di-di-dit 8 DAH- DAH- DAH-di-dit FCC 43 CHARACTERS: 9 DAH-DAH-DAH-DAH-dit LETTERS (26) 0 DAH-DAH-DAH-DAH-DAH A di-DAH PUNCTUATION & PROCEDURALS (7) B DAH-di-di-dit C DAH-di-DAH-dit BT DAH-di-di-di-DAH = (Note 1) D DAH-di-dit ? di-di-DAH-DAH-di-dit E dit / DAH-di-di-DAH-dit F di-di-DAH-dit , DAH-DAH-di-di-DAH-DAH G DAH-DAH-dit . di-DAH-di-DAH-di-DAH H di-di-di-dit AR di-DAH-di-DAH-dit + (N0te 2) I di-dit SK di-di-di-DAH-di-DAH (Note 3) J di-DAH-DAH-DAH K DAH-di-DAH PROSIGNS NEEDED FOR GOOD CW OPERATING, NOT IN THE FCC 43 L di-DAH-di-dit M DAH-DAH BK DAH-di-di-di-DAH-di-DAH (Note 4) N DAH-dit KN DAH-di-DAH-DAH-dit (Note 5) O DAH-DAH-DAH AS di-DAH-di-di-dit (Note 6) P di-DAH-DAH-dit @ di-DAH-DAH-di-DAH-dit (Note 7) Q DAH-DAH-di-DAH error di-di-di-di-di-di-di-dit (Note 8) R di-DAH-dit NOTES S di-di-dit T DAH 1.
    [Show full text]
  • Morse Code (Edited from Wikipedia)
    Morse Code (Edited from Wikipedia) SUMMARY Morse code is a method of transmitting text information as a series of on-off tones, lights, or clicks that can be directly understood by a skilled listener or observer without special equipment. It is named for Samuel F. B. Morse, an inventor of the telegraph. The International Morse Code encodes the ISO basic Latin alphabet, some extra Latin letters, the Arabic numerals and a small set of punctuation and procedural signals (prosigns) as standardized sequences of short and long signals called "dots" and "dashes", or "dits" and "dahs", as in amateur radio practice. Because many non-English natural languages use more than the 26 Roman letters, extensions to the Morse alphabet exist for those languages. Each Morse code symbol represents either a text character (letter or numeral) or a prosign and is represented by a unique sequence of dots and dashes. The duration of a dash is three times the duration of a dot. Each dot or dash is followed by a short silence, equal to the dot duration. The letters of a word are separated by a space equal to three dots (one dash), and the words are separated by a space equal to seven dots. The dot duration is the basic unit of time measurement in code transmission. To increase the speed of the communication, the code was designed so that the length of each character in Morse is shorter the more frequently it is used in the language. Thus the most common letter in English, the letter "E", has the shortest code, a single dot.
    [Show full text]
  • JOTA Activity Booklet KE4TIO
    1 2 3 Gulf Ridge Council Pack 415 KE4TIO Alan Wentzell (Operator) Amateur Call Signs Heard and Worked: __________________________________ __________________________________ __________________________________ __________________________________ __________________________________ __________________________________ __________________________________ __________________________________ States Contacted: __________________________________ __________________________________ __________________________________ __________________________________ __________________________________ __________________________________ __________________________________ __________________________________ Countries Contacted: __________________________________ __________________________________ __________________________________ __________________________________ Scouts Present: __________________________________ __________________________________ __________________________________ __________________________________ __________________________________ Akela’s Present: __________________________________ __________________________________ __________________________________ __________________________________ __________________________________ 4 Q Codes The “Q” code was originally developed as a way of sending shorthand messages in Morse Code. However, it is still used by operators for voice communications. Some of those in common use are listed below: QRA What is your call sign? QRM I have interference (manmade). QRN I am receiving static (atmospheric noise). QRT I am closing
    [Show full text]
  • Mnlilslffislßl SIGNAL BOOK UNITED STATES ARMY
    Uifh '^r MnlilSlffiSlßl SIGNAL BOOK UNITED STATES ARMY v 1916 WASHINGTON GOVERNMENT PRINTING OFFICE 1916 NOV 0 8 1988 WAR DEPARTMENT Document No. 500 Office ofthe Chief Sijnal Officer ADDITIONALCOPIES OF THIS PUBLICATION MAY BE PROCURED FROM THE•SUPERINTENDENT OF DOCUMENTS GOVERNMENT PRINTING OFFICE "WASHINGTON,D. C. AT 20 CENTS PER COPY V War Department, Office of the Chief of Staff. > Washington, April15, 1916. The followingSignal Book, prepared by the Chief Signal Officer of the Army,is approved and herewith issued for the information and government of the Regular Army and the Organized Militia of the United States. It supersedes Signal Book, United States Army, 1914, and its provisions willbe strictly observed throughout the service. order of the Secretary of War: H.L. Scott, Major General, Chief ofStaff. 3 CONTENTS. Page. Part I. General Instructions for Army Signaling 7 11. The American Morse Code 9 111. The International Morse or General Service Code. \u25a0 12 IV. Visual Signaling ingeneral 15 V. Visual Signaling by Flag, Torch, Hand Lan­ tern, or Beam of Searchlight (without shut­ ter) 17 VI. Signaling with Heliograph, Flash Lantern, or Searchlight (with shutter) 18 VII.The Ardois System 19 VIII.Signaling by Two-ArmSemaphore . 21 Stationary Semaphore 21 Hand Flags withTwo-ArmSemaphore Code. 21 IX.Letter Codes: Infantry .' 23 Cavalry. 24 Field Artillery ..... 24 Coast Artillery , 26 X. Conventional and Preconcerted Signals with Rockets, Bombs, Small Arms, Guns, Coston Lights, Very Pistols, etc 2828 XI.Flag Signals by Permanent Hoist. 31 XII.Conventional Telephone Signals 33 XIII.Emergency Signals '.. 34 XIV.Additional and Improvised Codes. 38 XV.
    [Show full text]
  • Morse Code [10Pt] History
    Morse code History 2013-June-11 Code pre-Morse Polybius, Greek historian from 150 BC, sent messages with torches, with numbers standing for letters. 1 2 3 4 5 1 ABCDE 2 F G H I,J K 3 LMNOP 4 QRSTU 5 VWXYZ that tied together to make national networks. Invention of telegraph In the Napoleanic wars both the French and the British set up towers Invention of telegraph In the Napoleanic wars both the French and the British set up towers that tied together to make national networks. Heartbroken to know that for days he was unaware of his wife's failing health and her lonely death he first began to think about how to do rapid long distance communication. The code as part of the telegraph: Morse Samuel Morse was a well-known painter. S F B Morse 1791-1872 In 1825 he was asked to paint the Marquis de Lafayette in Washington DC. Mid-way through he got a note that his wife was ill. He hurried home to CT, but was too late. The code as part of the telegraph: Morse Samuel Morse was a well-known painter. S F B Morse 1791-1872 In 1825 he was asked to paint the Marquis de Lafayette in Washington DC. Mid-way through he got a note that his wife was ill. He hurried home to CT, but was too late. Heartbroken to know that for days he was unaware of his wife's failing health and her lonely death he first began to think about how to do rapid long distance communication.
    [Show full text]
  • 1 めざせ 1 級！ 英語上級者への道 ～Listen and Speak Ⅱ～ 第 7 回
    めざせ 1 級！ 英語上級者への道 ～Listen and Speak Ⅱ～ 第 7 回 モールス信号 Script ■Dialogue for Introduction E: Hello, Tets. Thanks for posting so many photos of your wonderful journey to Europe on Facebook. I felt as if I were traveling with you on the continent. T: Yes, with social networks we now have almost instant communication. That’s a far cry from the days of snail mail. E: Indeed it is. But you know, Tets, there were some important interim communication technologies along the way. For example, do you know the origin of the acronym “SOS”? T: Ah! Dot dot dot /dash dash dash/ dot dot dot! That is one of the most famous acronyms represented by the telegraph code system developed by Samuel Morse in 1836. That system was also implemented later in radio broadcasting. “Save Oh Save” or perhaps “Save Our Souls”…there is some debate as to the original meaning! There was, however, Edward, an earlier version of this call for distress! Did you know that, my friend? E: Indeed I do! The original code was CQD! It may have meant “Come quickly: Distress!” But the dots and dashes used to indicate it were too long and… T: Stop! We will have to send a real distress call if we spill the beans about our lesson too soon! Let’s give our listeners a chance to experience this article for themselves. E: A fine idea! Let’s signal the start of this month’s study! T&E: Pip-pip-pip…pip-pip. ■Listen to the passage and answer the questions that follow.
    [Show full text]
  • Safety and Alarming Applications Using ISA100 Wireless
    Safety and alarming applications using ISA100 Wireless Yokogawa Electric Corporation Toshi Hasegawa 1 March 2016 Presenter Toshi Hasegawa is a Manager of standard department, Marketing Head quarters. Toshi has been working for Yokogawa Electric Corporation for 27 years, and he has worked for development of Distributed Control Systems (DCS). His current activity is mainly on standardization and marketing of industrial wireless network. 2 The History of Radio • Marconi had an early interest in science, and was especially interested in the work of Hertz • He quickly realized the potential of wireless transmission and filed a British patent – Awarded on 2nd July 1897, GB12039 • At 12:00pm on the 12th December 1901 Marconi sent and received the first Transatlantic radio transmission 3 The History of Radio • On Sunday evening 14th April 1912 the largest passenger ship in the world, Titanic struck an iceberg • The radio operators onboard were employed by Marconi International Marine • They sent a distress signal alerting the world and the Carpathia "CQD CQD SOS Titanic Position 41.44 N 50.24 W.·······” • Radio had proven it worth… Wireless safety application has been started over 100 years ago.. 4 Today’s topics 1) Motivation of wireless for plant safety 2) Benefits 3) Key requirements 4) ISA100 Wireless solutions 5) Applications 6) Summary 5 Motivation of adopting wireless for safety • Preventive measures – Process condition / status monitoring: Temperatures / Pressures / Flows / Levels / etc. – Asset condition monitoring: Vibration / Corrosion / Temperature / etc. • Accident avoidance / Limit the extent of damages – Alarm / Warning: Gas leak detection / Safety shower detection /Tsunami detection – Emergency shutdown: Remote valve control for safety mode • Human safety – People tracking on site / Communication to navigate for evacuation / etc.
    [Show full text]
  • Titanic Lessons.Indd
    Lee AWA Review Titanic - Lessons for Emergency Communica- tions 2012 Bartholomew Lee Author She went to a freezing North Atlantic grave a hundred years ago, April 15, 1912, hav- By Bartholomew ing slit her hull open on an iceberg she couldn’t Lee, K6VK, Fellow avoid. Her story resonates across time: loss of of the California life, criminal arrogance, heroic wireless opera- Historical Radio tors, and her band playing on a sinking deck, Society, copyright serenading the survivors, the dying and the dead 2012 (no claim to as they themselves faced their own cold wet images) but any demise. The S.S. Titanic is the ship of legend.1 reasonable use The dedication to duty of the Marconi wire- may be made of less operators, Jack Phillips and Harold Bride, this note, respect- is both documented and itself legendary.2 Phil- ing its authorship lips stuck to his key even after Captain Edward and integrity, in Smith relieved him and Bride of duty as the ship furtherance of bet- sank. Phillips’ SOS and CQD signals brought the ter emergency com- rescue ships, in particular the S.S. Carpathia. munications. Phillips died of exposure in a lifeboat; Bride Plese see the survived.3 author description This note will present some of the Marconi at the end of the wireless messages of April 14. Any kind of work article, Wireless -- under stress is challenging. In particular stress its Evolution from degrades communications, even when effective Mysterious Won- communications can mean life or death. Art der to Weapon of Botterel4 once summed it up: “Stress makes you War, 1902 to 1905, stupid.” The only protection is training.
    [Show full text]
  • Letter Circular 45: Construction and Operation of a Simple
    ' «i -•aif -ISe • 1-b Publication of the Letter DEPARTMENT OF COM'lERCE Circular BUREAU OF STANDARDS LC 45 WASHINGTON, D. 0. CONSTRUCTION AND OPERATION OF A SIMPLE RAD IOTELEGP.APHI C CODE PRACTICE SET.* (Prepared at request of the States Relations Service, United States Department of Agriculture for use by Boys 1 and Girls 1 Radio Clubs.) Introduction This pamphlet describes apparatus which may be used for the pur- pose of learning the radio telegraph code. The apparatus is very easy to set up and operate. It is intended to be used at radio club meet- ing places or in places where a number of radio students are accustomed to assemble. Those who construct the simple radio receiving sets des- cribed in the first two pamphlets of this series will probably hear many signals which are in code. The Code Practice Set is therefore made a part of this series so shat the international Morse Code may be learned. The cost of the complete outfit will be about $5*70 or, if one constructs the telegraph key, she. cost will be reduced to about $3«b0 It is assumed that those who use this outfit have radio receiving sets and can bring their telephone receivers (“phones") to connect to the other apparatus. It is also assumed that it will not be necessary to purchase the table upon which the parts are mounted. It is desirable *This is the third of a series of pamphlets describing the construction of radio equipment. The two publications which nave been issued are Letter Receiving Circular 43 , "Construction and Opera-cion of a Very Simple Radio Equipment," and Letter Circular 44, "Construction and Operation of a Two- Circuit Radio Receiving Equipment with Crystal Detector." These describe the construction and operation of simple receiving sets.
    [Show full text]
  • Morse Code Worksheets Morse Code Facts
    Morse Code Worksheets Morse Code Facts Morse code is used to send telegraphic information through two signal durations as dots and dashes that correspond to the alphabet, numbers, and punctuation. It transformed how people communicated with each other across long distances. HISTORY AND DEVELOPMENT ★ Samuel F. B. Morse, along with Leonard Gale and Alfred Vail, was able to develop a telegraph with a single circuit. Using this telegraph, the operator key is pushed down, sending an electrical signal to the receiver through a wire. ★ Around 1837, Morse and Vail developed a code that assigned a set of dots and dashes to the alphabet and numbers based on how often they are used in the English language. Samuel Morse, the inventor of Morse code KIDSKONNECT.COM Morse Code Facts ★ Simple codes were assigned to letters that are frequently used and those that are not used as often had more complex and extended codes. For example, the letter E, which is commonly used, is represented by while the letter Q is . ★ On May 24, 1844, Samuel Morse sent the first Morse telegraph from Washington, D.C., to Baltimore, Maryland. ★ In Samuel Morse's telegraph system, a paper tape is indented with a stylus whenever an electric current is received. Due to its mechanical components, the receiver makes a clicking sound whenever the stylus moves to mark the paper tape. A telegraph sounder (left) and key (right) The operators initially translated the message based on the indentations on the tape but soon they realized they could translate these clicks directly into dots (dits) and dashes (dahs) without the need to look at the paper tape.
    [Show full text]
  • Federal Communications Commission § 80.319
    Federal Communications Commission § 80.319 § 80.314 Distress communications. as practicable over a period of approxi- (a) The international radiotelephone mately one minute. The purpose of this distress signal consists of the word special signal is to attract the atten- MAYDAY, pronounced as the French tion of the person on watch or to actu- expression ‘‘m’aider’’. ate automatic devices giving the (b) These distress signals indicate alarm. that a mobile station is threatened by § 80.318 Use of alarm signals. grave and imminent danger and re- quests immediate assistance. (a) The radiotelegraph or radio- (c) The radiotelephone distress call telephone alarm signal, as appropriate, consists of: must only be used to announce: (1) The distress signal MAYDAY spo- (1) That a distress call or message is ken three times; about to follow; (2) The words THIS IS; (2) The transmission of an urgent cy- (3) The call sign (or name, if no call clone warning. In this case the alarm sign assigned) of the mobile station in signal may only be used by coast sta- distress, spoken three times; tions authorized by the Commission to (4) Particulars of the station’s posi- do so; or tion; (3) The loss of a person or persons (5) The nature of the distress; overboard. In this case the alarm sig- (6) The kind of assistance desired; nal may only be used when the assist- and ance of other ships is required and can- (7) Any other information which not be satisfactorily obtained by the might facilitate rescue, for example, use of the urgency signal only, but the the length, color, and type of vessel, or alarm signal must not be repeated by number of persons on board.
    [Show full text]