communication instructions radio telegraph procedure

UNCLASSIFIED ACP124 (D)
FIGURES
1 . ---- 4 ….- 7 --… O -----
2 ..--- 5 ….. 8 ---..
3 …-- 6 -…. 9 ----.
(NOTE: The figure zero is to be written with a slant superimposed unless the entire text consists
entirely of figures. The letter Z may be written with a horizontal line superimposed in
order to distinquish between 2 and Z. When this figure occurs in the text of messages
which consist entirely of figures or in weather messages which use the number of code, it
may be transmitted as "T" ("-"). On all other occasions the figure 0 is to be transmitted
as "-----". Transmission of 0 as the letter "O" is expressly forbidden.)
PUNCTUATION AND OTHER SIGNS
BLOCK (capital letters or underline) ..--.- COMMA --..--
FRACTION BAR (slant) -..-. QUESTION MARK ..--..
PERIOD (full stop) .-.-.- COLON ---…
HYPHEN or DASH -….- APOSTROPHE .----.
PARENTHESIS ACCENTED e ..-..
Left hand bracket -.--. ACCENTED a .--.-
Right hand bracket -.--.- ACCENTED ä .-.-
b. CHARACTER FORMULATIONS
(1) A dot is used as the unit of duration
(2) A dash is equal to three units
(3) An element is either a dot or a dash
(4) The space between elements is one unit
(5) The space between characters is three units
(6) The space between groups is seven units
108. TRANSMISSION TECHNIQUES AND TRANSMISSION SPEEDS
a. Each character shall be transmitted clearly and distinctly. The speed of transmission
shall be governed by the prevailing conditions and the capability of the receiving operation(s).
b. Accuracy in transmission is far more important than speed. The difference in time
required to send a message at 18 words per minute and that required to transmit it at 25 words per
minute is slight. Even this slight gain in time may be nullified by any added time required for repetitions.
(1) The speed at which the receiving operator can copy without having to obtain
repetitions is the speed at which the transmitting operator will transmit. When transmitting to more than
one station in a net, the governing speed of the transmitting operator is that of the slowest receiving
operator, but see (4) below.
(2) The speed of transmitting headings on manually operated circuits should be
slower than the speed of transmission of texts.
UNCLASSIFIED 1-5