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.

Morse Prosigns & Special Chars

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.