Morse code

International Morse encodes each character as a sequence of short and long signals — a dot (•, "dit") roughly 1 unit, a dash (—, "dah") roughly 3 units. Inter-element gap is 1 unit, inter-letter gap 3 units, and inter-word gap 7 units. The signal can be transmitted by radio key, by sound, or by light (Aldis lamp), making it the universal pre-digital backup for distress and identification.

Although GMDSS retired Morse as a mandatory distress watch in 1999, the alphabet remains in service for vessel-to-vessel light signalling, amateur and military radio, and as a fallback in degraded comms. The distress signal is three dots, three dashes, three dots — sent as one continuous group (…———…), not spelled as the letters S-O-S.

Audio generator

TextWPM

... --- ...

Try: SOS · MAYDAY · CQ DE · your callsign. Browser audio only — nothing is transmitted.

Alphabet

A.-

B-...

C-.-.

D-..

F..-.

G--.

H....

I..

J.---

K-.-

L.-..

M--

N-.

O---

P.--.

Q--.-

R.-.

S...

T-

U..-

V...-

W.--

X-..-

Y-.--

Z--..

Numerals

0-----

1.----

2..---

3...--

4....-

5.....

6-....

7--...

8---..

9----.

Punctuation

..-.-.-Period (AAA)
,--..--Comma (MIM)
?..--..Question mark (IMI)
'.----.Apostrophe
!-.-.--Exclamation
/-..-.Slash / fraction bar
(-.--.Open parenthesis
)-.--.-Close parenthesis
&.-...Ampersand (AS — wait)
:---...Colon
;-.-.-.Semicolon
=-...-Equals (BT — break)
+.-.-.Plus (AR — end of message)
--....-Hyphen / dash
_..--.-Underscore
".-..-.Quotation
@.--.-.At sign

Prosigns

A prosign is two or more letters keyed without the inter-letter gap, treated as a single procedural symbol.

SOS...---...Distress — sent as one unbroken group, not three letters.
AR.-.-.End of message.
AS.-...Wait.
BT-...-Break / new paragraph.
CT / KA-.-.-Start of transmission / attention.
K-.-Invitation to transmit (over).
KN-.--.Invitation to a specific station only.
SK / VA...-.-End of contact / signing off.
HH........Error — disregard last word.

Common Q-codes & abbreviations

CQGeneral call to all stations.
CQ DEGeneral call from this station.
DEFrom (precedes own callsign).
QRTStop sending / I am closing down.
QRXStand by / wait.
QSLI acknowledge receipt.
QTHMy position is…
QRMInterference.
QRNAtmospheric noise (static).
QRZWho is calling me?
MAYDAYDistress (voice equivalent of SOS).
PAN-PANUrgency.
SECURITESafety / navigation warning.
73Best regards (sign-off).
88Love and kisses (informal sign-off).

Light signalling

For ship-to-ship Aldis lamp work the dot is a brief flash and the dash a held flash, with the same proportional timing. The receiving vessel acknowledges each word with a single "T" (—) and a complete message with "R" (•—•). Misread letters are corrected by sending eight dots ("HH") and resuming from the last good word.