Using these Pages

When you are in the process of encoding a message, the top part of the page will look something like the following: (Note: In this example, only the navigation buttons are active, and the message is fixed).

Message:  YJIB CERS ELPG  YJIB 6058 Commanding officer s CERS 0816 91 st ELPG 1365 Division s (of)   (New group will be inserted before group selected by the radio button) O Z U Z 4144 Disapproved I H A M 2325 Do you I V N U 2663 Displine ary I D C M 2227 Does K A Z U 2949 Discretion L E K U 3110 – not I S Z R 2599 Dispatch es (No. s) O O F F 3880 Doing L O P E 3165 Dispense ing s (with) Y K E K 6079 Done D O O H 1014 Dispensed (with) E D S E 1167 Double ing s

The parts of the page have the following meanings:

• Message: YJIB CERS ELPG ...— This represents the telegram as it would be sent. Since Morse code doesn't distinguish uppercase and lowercase letters, the message is displayed in uppercase.
• Next comes the various code words (along with the code numbers and phrases) that make up the message. The "Delete" button can be used to remove each part of the message.
• Next come a set of buttons for navigating around the various pages. These buttons appear at the top and bottom of each page.
  • Introduction — Takes you to this introductory page
  • Table of Contents — This will take you to the table of contents (page 1)
  • Decode Section — This will take you to the first page of the decoding section (page 83)
  • Previous Page — Take you to the previous page (43 in this example).
  • Next is a textbox to display the current page number. To go to an arbitrary page, you can enter the page number here and press the "Go" button.
  • Next Page — Take you to the next page (45 in this example).
• Then is the contents of the current page. The "Add" button to the left of each phrase will add the corresponding phrase to the end of the message. If the current page has two columns, There is an "Add" button for each column.

Encoding a Message

The book includes an example of encoding messages on page 8-11. Here is my own example of encoding and decoding messages.

Suppose we want to send a message: "Do you have wireless connection with group HQ"

• We can start by looking for "Do". On page 44, we IHAM for "Do you".
• Next comes "Have", with three possibilities for "Has (have)" on page 49. For better security, we want to use all possible groups in different messages, so randomly select DOHA.
  • If there is a potential for confusion between tenses, the entries for "ed", "ing", etc., can be used to make it explicit.
  • Note we also could have encoded "Do you have" using the phrases "Do" and "You have".
• Going to page 75, there is no phrases for "wireless". But noting that "radio" is a synynom, we can find XIEX on page 63 meaning "Radio communication".
• The word "With" is on page 75, with five possible groups. Again choosing randomly, we can add HUVB to the message.
• On page 49 we find POZL meaing "group headquarters"
• Finally, go to page 17 to insert a null SUCD as the new second group in the message

So our final message is:

Page	Code Word	Phrase
44	IHAM	Do you
17	SUCD	Null
49	DOHA	Has (have)
63	XIEX	Radio communication
75	HUVB	With
49	POZL	Group headquarters

So assembling the message as "Do you have radio communication with group headquarters" we could encode it as:
 IHAM SUCD DOHA XIEX HUVB POZL 

Note that if the message included proper names or other words not in the code, then there are two options:

• If the name/word is likely to be used often, an appropriate authority can assign it one or more of the supplment groups (pages 77-82).
• For names or words that are not likely to be repeated can be spelled out using the entries on pages 28-31 (See the decode example below).

Decoding a Message

Suppose we receive the message:
 UREP EIHJ VIJD DEFT DOHA AFPF MITR YWGF EJHX OGVR YSVS IEBZ 

Take each of the code words, and look each word up in the decoding section of code book, finding:

Page	Code Word	Phrase
140	UREP	Attack progressing
97	EIHJ	Well
143	VIJD	Stop (period)
93	DEFT	Front line s
94	DOHA	Has (have)
84	AFPF	Reached
119	MITR	North (of)
153	YWGF	Null
97	EJHX	Edge s (of)
124	OGVR	Pas
152	YSVS	S
108	IEBZ	Y

So this message is "Attack making good progress. Front line has reached north edge of Passy."

Note that the code words are constructed so that valid groups differ by at least two letters. If a code word is incorrect and cannot be found in the decoding section, pages 12-16 describe procedures to fix the error and determine the correct code word.