These examples illustrate the convenience of
international procedure signals and signs:
The general call signal (or call for unknown
station) AA AA AA is made to attract attention
when wishing to signal to all stations within
visual signaling distance or to a station whose
name or identity signal is not known. The call is
continued until the station addressed answers.
The answering signal TTTT is made to answer
the call and it is continued until the transmitting
station ceases to make the call. The transmission
starts with the signal DE followed by the name
or identity signal of the transmitting station.
Example: When one of the stations is other than
an Allied naval ship,
STATION "A" TRANSMITS
STATION "B" TRANSMITS
AA AA (until answered)
TTTTT (until call ceases)
DE NABC KFLN KFLN
3. The letter T is used to indicate the receipt of each
word or group.
4. The erase signal EEEEEE indicates that the last
group or word was signaled incorrectly. It is answered
with the erase signal. When answered, the transmitting
station will repeat the last word or group that was
correctly signaled and then proceed with the remainder
of the transmission.
5. The repeat signal RPT is used as follows:
By the transmitting station to indicate that it is
going to repeat ("I repeat"). If such a repetition does
not follow immediately after RPT, the signal should
be interpreted as a request to the receiving station to
repeat the signal received ("Repeat what you have
By the receiving station to request a repetition of
the signal transmitted (Repeat what you have sent).
The special repetition signals AA, AB, WA, WB,
and BN are made by the receiving station as
appropriate. In each case, they are made immediately
after the repeat signal RPT.
RPT AB KL"Repeat all before group KL."
RPT BN BOATS SURVIVORS"Repeat all
between words boats and survivors."
If a signal is not understood or, when decoded, is
not intelligible, the repeat signal is not used. The
receiving station must then make the appropriate
signal from the Code, indicating Your signal has been
received but not understood.
6. A correctly received repetition is acknow-
ledged by the signal OK. The same signal may be
used as an affirmative answer to a question ("It is
7. The ending signal AR is used in all cases to
indicate the end of a signal or the end of a transmission.
The receiving station answers the signal RReceived
or I have received your last signal.
8. The transmitting station makes the signal CS
when requesting the name or identity signal of the
9. The waiting signal or period signal AS is used
When made independently or after the end of a
signal, it indicates that the other station must wait for
further communications (waiting signal).
When it is inserted between groups, it serves to
separate them (period signal) to avoid confusion.
10. The signal C should be used to indicate an
affirmative statement or an affirmative reply to an
interrogative signal; the signal RQ should be used to
indicate a question. For a negative reply to an
interrogative signal or for a negative statement, the
signal N should be used in visual or sound signaling,
and the signal NO should be used for voice or radio
When the signals N or NO and RQ are used to
change an affirmative signal into a negative statement
or into a question, respectively, they should be
transmitted after the main signal.
CY N (or NO, as appropriate)..."Boat(s) is (are) not
coming to you."
CW RQIs boat/raft on board?
The signals C, N or NO, and RQ cannot be used in
conjunction with single-letter signals.
Because of the apparatus used (whistle, siren,
foghorn), sound signaling is necessarily slow.
Moreover, the misuse of sound signaling could create