Morse Code Prosigns
Prosigns are procedural Morse signals used to mark actions such as the end of a message, a pause, a separator, or the end of work. Many are written with letter names such as AR or SK but sent as one continuous pattern without the normal gap between those letters.
That timing difference matters. AR sent as a prosign is one joined pattern, .-.-., rather than the letter A followed by a normal character gap and then R.
This page focuses on widely recognized joined signals and clearly separates them from punctuation, Q-codes, ordinary abbreviations, and operating codes whose treatment varies between references.
Morse Code Prosigns Reference
Use Play to hear the joined signal and Copy to copy its raw Morse pattern. The status label shows whether the entry is a routine procedural signal, a distress signal, or a common amateur convention that needs extra context.
In amateur and telegraph practice, AR is a common written name for this continuous pattern. ITU procedure uses the same .-.-. cross-signal pattern in message handling.
ITU procedure defines .-... as the wait signal, and amateur operating references commonly write the joined pattern as AS.
The same -...- pattern is the ITU double-hyphen signal. In CW practice it is commonly written as BT when used procedurally.
ITU procedure specifies ...-.- as the end-of-work signal. SK is the common amateur notation for this continuous pattern; some references also use VA for the same sound pattern.
SOS is not a routine message-control signal. It is included because its continuous timing illustrates the same no-letter-gap principle and it is commonly grouped with prosign references.
HH as eight dots is common in amateur Morse practice. Do not describe it as identical to the formal ITU error signal: ITU-R M.1677-1 specifies a seven-dot error signal in its formal transmission procedure.
What Is a Morse Code Prosign?
A prosign, short for procedural signal, is a Morse sequence used to control the flow of communication rather than spell an ordinary word. Common roles include marking the end of a message, asking the other station to wait, separating sections, or ending work.
Many prosigns are written with familiar letters because those letters provide a convenient name for the signal. The transmitted rhythm is the important part. When AR is used as the joined prosign, the normal gap between A and R is removed and the elements form one continuous .-.-. pattern.
This is different from an abbreviation. CQ, DE, QSL, and other shorthand are transmitted as ordinary characters with normal character spacing unless a specific operating convention says otherwise.
Why Prosigns Are Sent Together
Normal Morse letters are separated by a three-unit character gap. A joined prosign removes that internal letter gap, so the combined elements are heard as one signal.
Normal letters:
Joined prosign:
The dots and dashes have not changed; the spacing has. That is why learning only the written letters “A R” can be misleading if you do not also learn the continuous rhythm.
Common Prosigns Explained
AR — End of message
AR marks the end of message content. It is not the same as sending the ordinary letters A and R with a normal character gap; the prosign is the continuous pattern .-.-..
SK — End of work
SK is commonly used when the contact or work is finished. The joined pattern is ...-.-. Do not confuse ending one message with ending the entire exchange.
BT — Separator
BT, -...-, is used as a separator between sections or thoughts. The same pattern is also shown as the equals-sign/double-hyphen character in punctuation references, so its role depends on context.
AS — Wait
AS, .-..., requests a temporary pause or wait. The procedural meaning comes from using the joined signal in context, not from spelling the letters A and S as a word.
SOS — Distress
SOS is the international Morse distress signal ...---..., sent as one continuous group. It has a special distress function rather than the routine message-control role of signals such as AR or BT.
For history and a dedicated explanation, read SOS in Morse Code.
A note about HH and the error signal
Eight dits, written as HH in common amateur practice, are widely used as an error or correction prosign. Formal ITU-R M.1677-1 telegraph procedure specifies an error signal of seven dots. They should not be described as the same standardized signal.
A Simple CW Example
This schematic example shows how procedural signals can organize a short Morse message. It is an educational timing example, not a complete operating script or country-specific procedure.
CQ, DE, callsigns, numbers, and Q-codes are not automatically prosigns simply because they appear in the same exchange. The defining issue is how the signal is used and, for joined prosigns, how it is spaced.
Prosigns vs Punctuation
A punctuation mark represents a written character. A prosign carries a procedural meaning. Sometimes the same Morse pattern can serve both roles.
| Pattern | Typed-symbol role | Procedural role |
|---|---|---|
| .-.-. | Plus sign | AR — end of message |
| -...- | Equals sign / double hyphen | BT — separator |
| .-... | Ampersand in many Morse software charts | AS — wait |
The pattern alone does not always tell you which meaning is intended. Context and operating convention determine whether the sequence represents a printed symbol or a procedural signal.
For typed symbols and their standard status, see Morse Code Punctuation & Symbols.
Prosigns vs Abbreviations & Q-Codes
Prosigns, abbreviations, and Q-codes can appear in the same Morse exchange, but they are not the same category.
Prosign
A procedural signal used to control or structure communication. Joined prosigns such as AR and SK are transmitted without the normal character gap inside the signal.
Abbreviation
Ordinary letters or numbers used as shorthand. Examples such as DE or 73 are normally transmitted as their individual Morse characters with normal character spacing.
Q-code
A three-letter Q-group with an established operating meaning, such as QSL or QTH. A Q-code is not made into one fused Morse character simply because it is shorthand.
This page intentionally does not reproduce a Q-code or abbreviation glossary; those belong to their own reference topic.
For CQ, DE, 73, common CW shorthand, and Q-code question/statement forms, see Morse Code Abbreviations & Q-Codes.
Operating Signals with Varying Terminology
Not every CW reference draws the boundary around “prosign” in exactly the same place. This matters most for signals such as KN and BK.
KN
KN is widely used in amateur CW to indicate that only the named or called station should reply. Many modern charts and software group a run-together KN pattern with prosigns. However, the ARRL/IARU Ethics and Operating Procedures guide describes KN as two letters sent with an inter-character space and therefore does not classify it as a prosign in that convention.
BK
BK is widely used as an operating abbreviation for break or break-in. The same ARRL/IARU operating guide treats BK as separate letters rather than a joined prosign.
K
K is the ordinary Morse letter K, -.-, used procedurally as an invitation to transmit. Because it is already one normal Morse character rather than a fused multi-letter signal, this page does not place it in the joined-prosign chart.
For that reason, this page keeps KN, BK, and K outside the core joined-prosign cards instead of presenting one amateur convention as universal.
Common Mistakes
Adding a letter gap inside a joined prosign
AR sent as A, then a normal character gap, then R is not the same rhythm as the continuous AR prosign .-.-..
Treating every operating abbreviation as a prosign
CQ, DE, 73, QSL, and QTH are examples of other operating shorthand, not joined prosigns.
Assuming the written letters are transmitted literally
Labels such as AR and SK name a procedural rhythm. When written with angle brackets or an overline in some references, those marks are notation and are not extra characters transmitted on the air.
Ignoring punctuation overlap
A pattern such as -...- can represent a typed symbol or a procedural separator depending on context. Do not assign a procedural meaning from the pattern alone.
Treating every reference list as universal
Operating conventions vary. Signals such as KN are classified or spaced differently by different amateur references, so this page avoids presenting a disputed convention as universal.
Using SOS like an ordinary routine prosign
SOS has a specific distress function. It is shown here because of its continuous Morse timing, not because it is a routine separator or conversational control signal.
Technical references
International Morse character and telegraph procedures are documented in ITU-R recommendations, while amateur operating practice is also described by organizations such as ARRL and IARU. Terminology can vary between formal telegraph procedure and amateur operating guides, which is why this page labels special cases instead of treating every list as identical.
Frequently Asked Questions
What is a Morse code prosign?
A prosign is a procedural Morse signal used to control or structure communication. Many prosigns are written with letter names but sent as one continuous pattern without the normal character gap between those letters.
What does AR mean in Morse code?
AR is commonly used to mark the end of a message. As a joined prosign its Morse pattern is .-.-., sent continuously rather than as separately spaced A and R characters.
What does SK mean in Morse code?
SK is commonly used to indicate the end of work or the end of a contact. Its continuous Morse pattern is ...-.-.
Is SOS a prosign?
SOS is formally an international distress signal, sent as the continuous pattern ...---.... It is often grouped with prosigns because it uses the same no-letter-gap principle, but its function is distress rather than routine message procedure.
Are CQ and QSL prosigns?
No. CQ is an operating call and QSL is a Q-code. They are sent as ordinary Morse characters with character spacing rather than as one fused procedural character.
Is KN a Morse code prosign?
Terminology varies. Many modern amateur references group a run-together KN with prosigns, while the ARRL/IARU Ethics and Operating Procedures guide describes KN as two separately spaced letters and therefore does not classify it as a prosign in that convention. This page keeps KN outside the core joined-prosign chart for that reason.