PART A. STRUCTURE AND PURPOSE OF CALL SIGNS
1. Call signs are used primarily for establishing and maintaining communications. They
consist of any combination of characters or pronounceable words that identify a
communication facility, a command, an authority, or a unit. Periodic changing of call signs
provide communication security for a brief period, depending on the amount of use and the
quality of traffic analysis. Call signs that consist of three-to-six characters, such as 6B69 or
DN8Z, are used for radiotelegraph 9CW) and manual teletypewriter (including radio
teletypewriter), and are used for voice operation on AM equipment. To avoid confusing call
signs with certain procedural codes used by telegraph and teletype operators, three character
call signs normally do not begin with the letters Q or Z. Voice call signs that consist of
pronounceable words, such as BUTTER DIESEL, or ACHING BUNKER, are used for
radiotelephone operation. Sometimes voice call signs are referred to as call words.
2. Call signs may consist of any combination of characters or pronounceable word, and
identify a communication facility, a command, an authority, or a unit. Call signs are referred
to as OPEN when their identity is a matter of public knowledge, and SECRET when their
identity is withheld for reasons of security.
3. International call signs listed in the Beme Books are an example of open call signs. Call
signs of this type are allocated to the using stations by the communication authority of a
country in accordance with the policies established by the International Telecommunications
4. SECRET call signs are used by military, paramilitary forces, and other organizations which
have a reason for concealing their identity. Traffic analyst are primarily concerned with these
PART B: THE CALL-UP AND ABBREVIATED CALL
1. To let the receiving radio station know that a transmitting station is trying to contact it, and
to ensure that the receiving operator is ready to receive a message, a call-up is made. This
call- up serves to alert the receiving stations of a forthcoming message, and to identify the
station sending the message. The following examples depict the call-up.
EXAMPLE #1: ACDJ DE CEHN
EXAMPLE #2: YELLOWBIRD THIS IS GREENAPPLE
Example #1 shows a call-up using telegraph or teletype callsigns. Note the separator "DE"
between the call signs. This separator is a procedure signal which means "FROM" or
"THIS IS." The call sign to the right of the procedure signal is always the transmitting call
Example #2 shows a call-up using radiotelephone call signs or call words. The separator in
this case is called a procedure word, and is written just as it is heard over a voice net. Again,
the call word to the right of the separator is always the transmitting call word.
2. After communications have been established between two stations, an abbreviated call
may be used to reduce transmission time. In an abbreviated call, the transmitting operator