Does SOS mean "Save Our Souls"?

No. SOS was never an abbreviation. The sequence was chosen because three short, three long, three short with no letter gaps is unmistakable and recognisable even in noise. "Save Our Souls", "Save Our Ship" and "Send Out Succour" all came later.

Does CQD mean "Come Quick, Danger"?

Also no. CQ had long been the call to all stations in landline telegraphy; Marconi appended the D for distress. The phrase is a later mnemonic.

Is Morse code a language?

No, a script. It carries letters, digits and punctuation - which language they spell is all the same to it. You can send German, English or Japanese in Morse, but you cannot converse "in Morse", only in a language you already speak.

Is Morse code binary?

The channel is, the code is not. The transmitter knows two states, on and off - but the meaning lives in the lengths: dot one, dash three, gap within a character one, between characters three, between words seven. Throw the timing away and keep only zeros and ones, and nothing can be decoded. Morse is therefore not a binary code but a variable-length one.

Was the Titanic the first ship to send SOS?

No. The documented first is the RMS Slavonia in June 1909, followed two months later by the SS Arapahoe. The Titanic alternated CQD and SOS - and after that CQD disappeared.

Is Morse code still used?

Yes, just not at sea. For maritime distress it was replaced on 1 February 1999 by the satellite-based GMDSS. In amateur radio it is alive because it gets further on less power than any other mode; aviation beacons still send their identifier in Morse, and armed forces continue to teach it.

How fast can Morse code go?

The record has stood since 1939: Theodore Roosevelt McElroy copied 75.2 words per minute at a contest in Asheville - on a typewriter. Some sources give 75.6. In everyday practice 20 to 30 words per minute is skilled work, and even 20 is more than most ever reach.

What is the difference between Morse code and CW?

Morse code is the character set, CW the mode of transmission. CW stands for continuous wave: an unmodulated carrier keyed on and off. You can send Morse code with a torch, a horn or by knocking - that is Morse code, but not CW.

Did Samuel Morse invent the code alone?

No. Alfred Vail had a substantial part in developing it, and the version valid internationally today goes back to a revision by Friedrich Clemens Gerke in 1848. The code carrying Morse's name is not the one Morse wrote down.

Morse code myths

Few technologies attract as much false retelling - usually because the wrong story is the better one.

Why these errors persist

Almost every Morse myth is built the same way: someone looks for meaning after the fact in something that is the way it is for practical reasons. SOS was not chosen because it means something, but because you cannot miss it. "Save Our Souls" came afterwards - and it sounds so good that it has lasted a century.

Such retro-fitted readings are called backronyms. They are not malicious, merely wrong, and they crowd out the more interesting answer: that somebody thought hard about audibility.

Frequently asked questions

Does SOS mean "Save Our Souls"?
No. SOS was never an abbreviation. The sequence was chosen because three short, three long, three short with no letter gaps is unmistakable and recognisable even in noise. "Save Our Souls", "Save Our Ship" and "Send Out Succour" all came later.
Does CQD mean "Come Quick, Danger"?
Also no. CQ had long been the call to all stations in landline telegraphy; Marconi appended the D for distress. The phrase is a later mnemonic.
Is Morse code a language?
No, a script. It carries letters, digits and punctuation - which language they spell is all the same to it. You can send German, English or Japanese in Morse, but you cannot converse "in Morse", only in a language you already speak.
Is Morse code binary?
The channel is, the code is not. The transmitter knows two states, on and off - but the meaning lives in the lengths: dot one, dash three, gap within a character one, between characters three, between words seven. Throw the timing away and keep only zeros and ones, and nothing can be decoded. Morse is therefore not a binary code but a variable-length one.
Was the Titanic the first ship to send SOS?
No. The documented first is the RMS Slavonia in June 1909, followed two months later by the SS Arapahoe. The Titanic alternated CQD and SOS - and after that CQD disappeared.
Is Morse code still used?
Yes, just not at sea. For maritime distress it was replaced on 1 February 1999 by the satellite-based GMDSS. In amateur radio it is alive because it gets further on less power than any other mode; aviation beacons still send their identifier in Morse, and armed forces continue to teach it.
How fast can Morse code go?
The record has stood since 1939: Theodore Roosevelt McElroy copied 75.2 words per minute at a contest in Asheville - on a typewriter. Some sources give 75.6. In everyday practice 20 to 30 words per minute is skilled work, and even 20 is more than most ever reach.
What is the difference between Morse code and CW?
Morse code is the character set, CW the mode of transmission. CW stands for continuous wave: an unmodulated carrier keyed on and off. You can send Morse code with a torch, a horn or by knocking - that is Morse code, but not CW.
Did Samuel Morse invent the code alone?
No. Alfred Vail had a substantial part in developing it, and the version valid internationally today goes back to a revision by Friedrich Clemens Gerke in 1848. The code carrying Morse's name is not the one Morse wrote down.

Keep going

What is Morse code

Timeline

SOS

Titanic

Famous messages

History