Here is the training video used to teach soldiers how to use the
M-209 unit. It runs 31 minutes, 48 seconds. Also the sound is
very low so you may need to boost your volume. The video tracking
is bad; If you have a better video copy, I'd be happy to get
it digitized and posted.
The videos are on YouTube here:
- Reel 1
- Reel 2
- Reel 3
I really enjoy the opening music and the voice over artist. The music seems to announce a
really interesting film, but it surely put people to sleep within the first few minutes. And
I'm sure I've heard that voice before. Was he the "Drop and Cover" announcer from the
Thanks to my friend Bill for converting this video into Quicktime!
Transcript of the Film
Official Training Film
T.F. 11 – 1400
One of our messages in the hands of the enemy may lose a battle, but if that message is
cryptographed, the enemy will lose enough time figuring it out to make the information
useless. To help you cryptograph more effectively, this converter, the M-209, has been put
into use throughout out the Army. There are several models of the M-209; all operate the same
way. To see how, let’s encipher the simple word “GO”.
Whenever you encipher, be certain that the encipher/decipher knob is at “C”. Set
the letter “G” on the indicating disk, opposite the indicating index. Turn the
drive knob as far as it will go. Set the letter “O” opposite the indicating
index. And turn the drive knob once again. The result is the word “go” in cipher.
Now let’s decipher it.
First, set the cipher/decipher knob to “D”. Next, reset the letter counter
to zero. Set the letter “X” opposite the indicating index, then the letter
“Z”. Here is what we get: our original word “GO”.
This system of cryptographing is known as “cipher substitution”, which
simply means that different letters are substituted for the ones you set up. In this case,
“X” was substituted for “G”, and “Z” for “O”.
This substitution is brought about by the interaction between the lugs on these drub bars,
and the pins on these key wheels. In order for your message to be deciphered, the pins
and lugs of both your converter, and that of your receiving operator, must be set exactly
alike. Charts are provided to tell you how to set them.
Assuming that this converter is already set according to a chart, let’s encipher this
message. Set the cipher/decipher knob to “C”. Then set the letter counter to zero
by pushing down the reset button and turning the reset knob until the counter clicks into
position. In order to make the cryptogram difficult to break down, 6 revolving key wheels are
used. The first step is to rearrange them in any order you desire. Do this with your thumb or
fingers; a hard object like a screwdriver will mangle the letters and ruin the wheel grooves.
The 6 letters now lined up along this benchmark form what is known as the “external
message indicator”. Since you have to refer to it later, this external message
indicator is always written down. And here’s an important point: you use an external
message indicator only once with in conjunction with a particular pin and lug setting. Now
select at random any letter at random on the indicating disk. In this case, we’ll take
“L”. Record it along with the external message indicator. Next encipher
“L” 12 times. From these 12 letters we have to form still another 6 letter
combination which will be the “internal message indicator”.
First reset the counter to zero. Then set the first letter “J” on the first
keywheel. Set the second letter “W” on the second keywheel. But there is no
“W”! A flaw in the machine? Not at all! Certain letters are deliberately omitted
from the 2nd, 3rd, 4th, 5th, and 6th keywheels. Whenever one of the 12 enciphered letters
can’t be found on the keywheel, it’s crossed out and the next letter used.
Let’s try “U” for the 2nd keyweel. Yes! Since it’s here, we can use
Next is “P” which goes on the third keywheel. It too can be used. Now
“D”. The next letter is “J”. Next is “R”. But
“R” isn’t on the sixth keywheel. So we cross it out and try the next
letter, “S”. No “S” either, so it too is crossed off. Now let’s
try “G”. “G” is OK, so we’ll use it. We have now set up an
internal message indicator from the twelve cipher letters. Since we have the keywheels lined
up, we must destroy the twelve cipher letters for security sake.
All right! We’re now ready for the message. Set each letter on the indicating disk and
encipher it. Notice that as each letter is enciphered, the letter counter is registered. This
gives the operator a check on the letters he has already enciphered and is useful in locating
errors. The next letter, “U”, is already in place on the indicating disk. In such
a case, turn the disk in either direction to release the drive knob. Then set up the letter
again, and continue enciphering the message.
At the end of each word, encipher the letter “Z”. Later when the message is
deciphered, “Z” will come out as a blank space, separating the words. Where a
single letter occurs, use the phonetic name. In this instance, “EZ” for
“E”. This use of phonetic names for single letters helps to prevent errors in
enciphering and deciphering and in transmitting.
Since there are no numbers on the indicating disk they must be spelled out.
“T-W-O” for “2”, and so forth. When you are finished, roll out a few
extra inches of tape before tearing it off. Here is the enciphered message. Notice that the
last group contains only three letters. Since the M-209 enciphers in five letter groups, it
is necessary to complete this group by writing in two “X”s.
Now we have to add three indicators that go before and after every M-209 cryptogram. The
first indicator is obtained by repeating the letter we originally enciphered twelve times.
The letter “L” in this case. This is known as the “system indicator”,
and tells the receiving operator that the message was enciphered on the M-209. The second
indicator is the “external message indicator”. The six letters we selected at
random and set up on the key wheels before. Remember we wrote it down for later use. This is
it. The third indicator is the “key list indicator” which tells the operator what
chart to use for his pin and lug setting. OK, we have our three indicators, the repeated
letter that tells us a converter was used, the six letters selected at random forming the
external message indicator, and the key list indicator for the pin and lug setting. Notice
that we separated the first three letters of our “external message indicator”
from the last three, to get five letter groups. All we have to do now is to transfer the
message onto the proper blank, and then dress it up with the necessary information for
forwarding. Finally, always turn the key wheels so that the internal message indicator is
broken up. The message may now be sent to its destination by any of the Army’s various
forms of communication. Ours is going by radio.
Here it is arriving at another message center. Let’s see how it’s deciphered. The
repeated letter “L” tells the operator that an M-209 converter was used. The key
list indicator tells him what chart to use for the correct pin and lug setting. In this case,
we’ll assume that the converted is already set according to the chart. To decipher the
message, the operator starts by following the identical procedure used when enciphering. He
sets the counter to zero, and the encipher/decipher knob to “C”. Next he picks
out the external message indicator and sets his key wheels in accordance with it.
Now he takes the repeated letter “L” and enciphers it twelve times. From this, he
obtains the same internal message indicator that the sending operator used. He zeroes the
letter counter, then sets up each usable letter on the six key wheels. Since the letter
“W” is missing from the second keywheel, he has to setup the next letter,
“U”. The he continues with the remaining letters. Here’s the result: the
original internal message indicator. Now he can start deciphering. First the
encipher/decipher knob goes to the “D” position. Then beginning with the first
letter after the indicator groups he sets each letter in position on the indicating disk and
deciphers it. When deciphering, the spaces between the letter groups are disregarded. All the
“X”es at the end of a message must be deciphered because the receiving operator
doesn’t know if they have merely been written in or are an actual part of the
Here’s our original message. Let’s compare it with the cryptogram. It’s
obvious that the last two X’s are meaningless so the operator crosses out the
corresponding letters. The letter “Z” which we put in after each word in the
original comes out as a blank thus spacing the word. Since it comes out as a blank, it must
be filled in where it obviously belongs, as with the Z in “zero”.
The last step is to turn the key wheels to break up the internal message indicator, and to
destroy all work copies of the code just as we did after enciphering. The message can now be
transferred to a blank, dressed with the necessary information, and sent to the addressee.
Now that we have enciphered and deciphered a complete message, let’s go back and study
in detail the pin and lug settings that are the key to the converter M-209. The pins for each
letter on the 6 keywheels are movable. So are the lugs on the metal bars of the drum. The
charts used to set up these pins and lugs are changed every day so whenever a message is
either sent or received the charts must be checked for the proper pin and lug settings. These
letters and dashes indicate the pin positions. A letter means that the pin goes to the right.
A dash means that it goes to the left. Before making a setting, all pins must be moved to the
left. Now that this is done, we can set them according to the chart. In the first column is a
dash, therefore the pin of letter “A” goes to the left. But this pin is already
on the left so you don’t need to touch it. Letter “B” means the pin of
letter “B” on the first keywheel must be pushed to the right. The same with
“C”, the pin goes to the right. Be sure that each pin is pushed all the way so
that it is flush with the side of the keywheel. An improperly set pin may slide into the
wrong position and cause an error.
Another dash. You don’t have to move “D” pin since it’s already to
the left. Continue this way until all the pin positions indicated on the chart have been set
on all the key wheels. Now you are ready to tackle the problem of setting the lugs.
These numbers on left of the chart, one through twenty-seven, represent the 27 drum bars.
While these numbers here correspond to the numbers on the number plate. For drumbar number 1,
the lug positions are for 3 and 4. Therefore on bar number one the lefthand lug is moved into
position 3. The righthand lug is set in position 4. Be sure each lug catches firmly in its
correct position. For drumbar number 2, the lug positions are 0 and 4. Therefore on bar
number 2, the lefthand lug is moved into the zero position, and the righthand lug is moved
into position 4. And so on until all the lugs are set.
To make sure all lugs and pins are correctly placed, you check against this group of letters
at the bottom of the lug chart. It’s called the 26 letter check. Here’s how
it’s done. Set the counter to zero, and the encipher/decipher knob to “C”.
Then turn all 6 keywheels to “A”. Now encipher 26 A’s one after another.
The result should match exactly the 26 letter check. If it doesn’t, a lug or ping has
been incorrectly placed and the positions must be rechecked against the chart. In this case,
the letters check and the converter is ready for enciphering or deciphering.
Now a few special points. First the jamming of the machine. When the drive knob hasn’t
been turned completely, the indicating disk won’t move. Complete the turn and the disk
is free. Next, in resetting the number counter, be sure the reset knob snaps firmly into
place so that all the zeros are exactly in line. Otherwise jamming occurs. The machine will
also jam if a pin or lug is partly out of position. Then the converter must be checked
thoroughly until the faulty adjustment is found and corrected.
To put in a new roll of tape, release the cover and tilt it back. Then release the guard and
pull it forward. Place the roll so that it will unwind counterclockwise. Thread the tape
through the tape slot and feed the end through the tape channel under the roller. Several
turns of the feed knob will bring the tape into position.
To replace the ink pad, push the spring arm to one side and remove the pad with the tweezers.
Be sure not to open the fresh inkpad container over the converter. The ink may spill or the
pad itself may fall into the mechanism. Push the spring arm to the side, and slip the new pad
into position. Both ends of the inkpad may be used so when one end becomes dry, the pad is
simply reset in the reverse position.
About every 250 operating hours the converter must be oiled. Again, don’t open the oil
container over the converter. An excess of oil may gum up the works.
To clean the typewheel, use type cleaner with the brush, turning the disk until all the dirt
Some models of the M-209 have plastic parts which should never be cleaned with chemicals. For
example, this wheel. Use only a dry brush for cleaning such models.
This reproducing disk shows exactly that letter which appears on the tape each time a letter
is enciphered. Should an operator run out of ink or tape he can still cryptograph a message
by recording the letters off this disk.
Finally, if you’re in immediate danger of capture, burn the signal operation
instructions page by page. Then set all the pins to the left, and all the lugs to zero. When
this is done, destroy the machine with an ax, or any other handy object. Rifle fire or a
grenade will also do an effective job of destruction.
Now let’s have a quick review of the whole procedure of enciphering and deciphering.
Assume the pins and lugs are set and checked according to the chart. The encipher/decipher
knob is set to “C”, the letter counter at zero. Set up your external message
indicator. Six letters selected at random that don’t spell an actual word, and record
them. Next, choose any letter. Record it, then encipher it 12 times. Select the
internal message indicator from these 12 letters. Then encipher the message. Remember that
phonetic names are used for single letters, but numbers must be spelled out. And that the
letter “Z” must be enciphered between words for spacing. When necessary, add
X’s to complete the last 5 letter group. Now in the same order before and after the
text, write the system indicator, the external message indicator, and the key list indicator.
Finally, transfer the message to a form and complete it. When you decipher a message, you
begin by following the identical procedure used when enciphering. The repeated letter informs
you that the message was enciphered by an M-209. And the key list indicator tells you what
pin and lug setting has been used. In this case it’s the one already on the machine, so
you’re ready to begin. First set the counter to zero. Next, look for the external
message indicator and set the key wheels in accordance with it. With the encipher/decipher
knob at “C”, encipher the repeated letter 12 times. After this is completed set
the counter to zero again. Select the internal message indicator from the 12 letters. Turn
the encipher/decipher knob to “D”, and decipher each of the letters in the
cryptogram including any X’s at the tail end. Roll out sufficient tape before tearing
so as not to lose any of the message. “Z” deciphers as a blank space, so fill it
in where necessary. Transfer the deciphered message to a message blank, address it, and then
forward. And finally, break up the internal message indicator after each message is
cryptographed. And destroy all work copies of the work tape.
Converters are used under various conditions, at higher headquarters, in foxholes, in the
open. Some of the conditions don’t include tables or shelves. At such times, the
operator can attach the converter to his leg by means of the carrying strap, and have both
hands free to operate. When not in use, the converter is always kept in its canvas case to
protect it from dirt and dampness. The converter is a valuable piece of equipment, but
it’s still equipment. In order to perform its job of confusing and delaying the enemy,
it has to be carefully protected and properly operated. That’s up to you.