A prosign, or procedural signal, is two or more letters sent together with no gap between them, forming a single distinct Morse symbol. They are operating shorthand, for example AR for end of message and SK for end of contact.

How are prosigns written?

On paper prosigns are usually shown as the component letters with an overbar or in angle brackets, like AR or . This tool uses angle brackets so you can type them on any keyboard.

What spacing does Morse use?

Within a letter, elements are separated by one unit. Between letters there are three units, shown here as a single space. Between words there are seven units, shown as a slash. Prosigns deliberately omit the inter-letter gap.

Which prosigns are supported?

AR end of message, AS wait, BT break or new paragraph, CT attention, KN go ahead named station, SK end of contact, SOS distress, VE understood, and HH error. These are the common ITU and amateur radio operating signals.

Can decoding always recover prosigns?

Only the unambiguous ones. SK, SOS, HH and VE have unique Morse patterns and decode back to their prosign. Others such as AR share a pattern with punctuation, so on decode they resolve to that punctuation instead.

What is the Morse Prosigns & Special Chars?

Encode and decode Morse code including ITU-R M.1677 punctuation and operating prosigns like AR end-of-message, SK end-of-contact, and BT break. Prosigns are sent run-together with no inter-letter gap, exactly as on the air. Runs in your browser. It runs free in your browser on Gera Tools, with nothing uploaded.

Morse Prosigns & Special Chars

Name: Morse Prosigns & Special Chars
Creator: Gera Tools
License: https://creativecommons.org/licenses/by/4.0/

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Standard Morse charts stop at letters and digits, but real on-air traffic relies on punctuation and operating prosigns. This tool extends Morse to the ITU-R M.1677 punctuation set and the common prosigns used in CW operating.

How it works

Each character maps to a sequence of dots and dashes from the international Morse table. Spacing carries meaning, measured in element-length units:

intra-character gap : 1 unit  (between dots/dashes)
inter-letter gap    : 3 units (shown as a single space)
inter-word gap      : 7 units (shown as a slash, /)

A prosign is several letters run together with no inter-letter gap, producing one continuous symbol. For example <AR> is A .- immediately followed by R .-., sent as .-.-. with no break — which is why it forms its own distinct pattern.

Tips and notes

Type prosigns in angle brackets: <AR>, <SK>, <BT>, <KN>, <SOS>.
When decoding, leave a single space between letters and a / between words.
A few prosigns share a Morse pattern with punctuation (for instance <AR> equals +); on decode the tool returns the punctuation for those, and the unique prosigns such as <SK> and <SOS> are recovered as prosigns.

The full prosign reference

Prosign	Notation	Morse	Meaning
AR	`<AR>`	`.-.-.`	End of message / over
AS	`<AS>`	`.-...`	Wait / standby
BT	`<BT>`	`-...-`	Break / new paragraph
CT	`<CT>`	`-.-.-.`	Attention / start copy
KN	`<KN>`	`-.--.`	Go ahead — named station only
SK	`<SK>`	`...-.-`	End of contact / clear
SOS	`<SOS>`	`...---...`	International distress
HH	`<HH>`	`........`	Error / correction
VE	`<VE>`	`...-.`	Understood

These cover the most commonly encountered prosigns in amateur CW, maritime, and emergency communications.

ITU-R M.1677 punctuation in Morse

The ITU-R M.1677 recommendation also standardises punctuation marks. Some key ones:

Character	Morse
Period (.)	`.-.-.-`
Comma (,)	`--..--`
Question mark (?)	`..--..`
Apostrophe (‘)	`.----.`
Exclamation (!)	`-.-.--`
Slash (/)	`-..-.`
Open parenthesis	`-.--.`
Close parenthesis	`-.--.-`
Colon (:)	`---...`
Double dash (=)	`-...-`
Plus (+)	`.-.-.`

Note that some punctuation shares a pattern with prosigns — the plus + has the same Morse as <AR>, and the equals sign = shares a pattern with <BT>. In text-to-Morse encoding, the tool sends the symbol as written. In decoding, ambiguous patterns are returned as the punctuation character since that is the more common interpretation.

Why prosigns matter on the air

In voice radio communications, you say “over” or “out.” In CW (continuous wave / Morse code), there is no room for words between transmissions — you need a compact, unambiguous signal that both operators recognise instantly. Prosigns fill that role.

<AR> after a transmission tells the receiving operator you are done and awaiting a reply. <SK> signals that the conversation is ending entirely. <KN> directs a response to a specific station when a net is active and other stations are listening. These conventions come from maritime and military telegraphy and were standardised by the ITU for international interoperability.