REF 

310 Seeoni Street,, S.E. 

Washington 31 D.. C • 

6 September 1953 

Rear Adrrl.ral Joseph R. Redman,. t:BN, Ret. 

Vice President 

Western Union Telegraph Can.pany lk05 o Street, N,w. 

Washington, D. C. 

Dear Joez 

/ In goi..Tlg through a drawex'.f'ul o.t' etutf' awaiting attention 

I came across the enclcsed copy of m.v u.s. Patent No. 21 552,.$£.a,, 

dealing with a !'acsi?dle enciph.ftt"ing system. The patent appli- cation on this one was held in a secrecy atatus tor a number 

of ;y&anJ1 but was :anally released in Ma.Y" 1951. 

Would yau be good enqugh to send it to the spprc>priate 

divieion in Western Union ;whenJ somebody would give it oonsideration tor possible ueef'ulnescr in Western Unionta work 1n the 

.f'ield of tacsintl.le apparatus. 

I would be glad to loarn o:t the resu1t of tho study, even 

i.t' the idea behind the patent tui'1'8 out to be of' negligible interest to Western Union. 

s~. 

WILLIAM F. FR.IEDMA.N 

l Inolosure 

_.,.. 

../ 

@'pp roved for Release by NSA on 09-13-2013 pursuantto E .0. 1352a 
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REF ID:A104975 

Patented May 15, 1951 2 552 54·g 

' ' 

Q:fFICE_ 

2;552;548 

FACSIMThE ENCIPHERIN6'SYSTEM _ 

wiiliani 1F:Friedman, Washington, D. c. 

Application,March_6, 1943iSeria1•No: 478;193 · 

5 Claims .. (Cl. 17S.,......5.ll 

(Granted:tunder.~the: act of March 3, 1883, as amendedrApril 30, 1928; 370 0; G. 757) 

1 

The invention described herein' may '.be-.mariu·-

factured and used by or for the Government 'for 

governmental purposes,- without the .payment to ·me of::any royalty1thereon~L 

The 'subject matter of this:invention is.'.a:·sys:.. 

tern for·_ enciphering : facsimiles:· 

This-. invention :relates to ·means; for ~secretly 

communicating ·information·. by · trarismi.tting -a 

facsimile of ·the -~·message: irr: a ·graphic• form•· of 

any sort .such as: a. writing; ·type-writing;· pie:. 

ture, photograph:or. the-like. ·Secrecy:·i.S obtained 

by· transmitting_ a: series" of_ impulses '.caused·'.in 

part .by the· message to be transmitted; and:·in 

part by 1 a control. :in~ ·-graphic!; form~ such1 as ~any 

writing;· picture ·or· random ·arrangement' of• dots or lines;. StJ.Ch .. ·a. control.' does: not·: necessarily 

have any intelligibility in'.·itself.. It·:operates ;as a random· key: At- the· receivingrend;~ a.::dupli'-

cate of· this control is:employed~· This';duplicate 

control ·is.moved in. synchronism ·.withothe move- ments of the·controh1.t~.the~transmitting1end<1md 

causes a. series of impulses·1which· co:.:operate~with 

the impulses ·received from:: the! transinitter ,r::the 

interaction between the two:·series :of-:-iinpul.Ses 

serving to produce: a·: facsimile of: the ·'original 

message. 

It is an object,. therefore, ofc my·:invention11to 

provide apparatus:comp1isingra:transmission,sys:. 

tem including. a. transmitter;·section~and•:'.a/.re::. 

ceiver section. ·Each:-of said· sections1chas;r as1.a 

part· thereof, an electric ·.circuit. including:. the 

contacts of ·a. plurality· of. relays' interconnected 

in.such:a way ·as ·to cause ·a: plurality. ofi impulses 

to .circulate in said circuit.. In the~'.transmitter 

section .these impulses· represent.:the.·:combined 

effects dtie ·to the message •to,be--transmitted:-arld 

to.a control element. An impulse·canconly- occur in. this circuit when both-of. the• relays'·nave• not 

moved their- contacts ·to 1tlie 1'same'pasitiorL• In 

the· receiver section ti-iese- · impulSes . represent 

those caused by ·the· origiilaF message;' sinceLthe 

impulses due to the control· have been''removed 

by the use of a duplicate cif<the ·coriti"ot:''iri·1the 

receiver section. 

For· a further expositionrof·my inventfon refer~ 

ence may be had to the annexed' dfaviirigs ~and 

specification at the end whei"eof"the' nover"fea~ 

tures of my invention will be specifically· pointed 

out· and claimed. 

In·the draWings: 

Figure 1 is· a circuit· diagram of• :the' transmit'!. 

ter 'with· parts~·designated by ·blocksGbeari.ng;'ap• 

propriate labels. 

Figure. 2 · is: a: tabulation· illustrating:; the im"-

pulses·.comprising the.intelllgence:tran8mittea!. 

2 

Figure• 3 'is a circuit· diagram of' the receiver 

in1block form. 

In the one embodiment of my invention· which 

lias been selected"from among others, my,device 

[, is · shown as comprising a transmitter section 

having a motor I driving shaft 2 carrying trans'- . parent drum 3 surrounded by message sheet ·4 

and also carrying transparent drum 5 surrounded 

by control sheet 6. Within drums•·3·:·and<5!are 

JO located electric lamps l' and 'B which. serve .

1 as sources of' light and which- are ·energized'from: a source of electricity 9. Opposite lamps l ·and.'B 

so as to receive a beam of light therefrom .and, 

respectively, under the control of message .sheet 

15 '4 and .. control sheet 6; are located light~sensi:. 

tive cells I 0 and 11 which form · pa1'ts of· circuits including amplifiers · 12 and 13 and.-'relay 

coils· 14 and 15. These ·relays· also iriclude mov:.. 

able contacts 15 cand 1 l biased in one· direction 

!!O 'by springs 18 and 19:and, in the other direction, 

by coils 14 and· 16, respectively, when these :coils 

are' energized, and engaging one or the other of 

stationary contacts 20 and ,21. Contacts 16; 1 l, 

2'0 •and 21 . form parts of a circuit, including a 21> 1

source -of current 22 and relay coil 23, which, 

when energized; attracts movable contact 24 into 

engageinent·. with stationary contact 25; over:. coming the pull- of spring 26: Contacts -2·4 ·and 

25 control a· circuit including transmitter -21 

;,;D having an output element 28;· shown as an--an'-

tenna. , At 'ther·place to which it· is desired ·to transmit the •iritelligence; there is located a· receiving 

system having a receiving element, indicated ,,,, as· an antenna 29, forming part of receiver 

·30 ·-which is ·connected into circuit so. as· to con- trol relay coil" 31. This relay also includes· mov- able contact 3·2 ·stressed away from coil 31 by 

spring 33 and co-operating with stationary con- 40 tacts 1

34. 'Motor 35 drives shaft 35 carrying trans"-

parent drum 31 surrounded by second control 

sheet i39, which is a duplicate of control sheet 

6: Within 'drum 31 is located electric lamp 39, 

energized by a source of electricity 40. Oppo45 site lamp 39 so as to receive a beam of light 

therefrom under the control of second ·control 

'sheet 38, is located light-sensitive· cell 4 ! which 

forms a .. part of· ·a circuit including amplifier 42 

and 'refay·coil 4-3: This relay also includes mov:. 

·50 able contact ~4'biased in one direction by-spring 

45·:and, ih- the o'th'er 'directicm, by coil :ll:J,' when 

this· coil is energized, so as ·to .. engage one--'or 

the.other of stationary contactsr4G:· Contacts)34 

·and:46.form·.parts1.of1a•Circuit >including a •source 

65 ·of.o·electricity;4l :arid a•}relay .. ·coil 148;; :TD.is. re~ 
REF ID:A104975 

2,552,548 

3 4· 

lay includes movable contact 49 stressed away duced in coil 48, which is represented in Figure 2 

from coll 48 by spring 50 and co-operating with by the line labeled "Message." Following 

stationary contact 51. Contacts 49 and 51 are through the other columns of Figure 2 shows 

parts of a circuit including a source of electricity that when coils 31 and 43 are simultaneously 

52 and coll 53, which is the operating element ti energized or de-energized, no impulse appears in 

of a facsimile reproducer of any convenient type. coil 48. Likewise, while either coil 31 or 43 is 

The operation of my device is as follows: The energized when the other is de-energized, coil 48 

message and the control sheets are in any graphic is energized. The energization of coil 48 causes form such as a writing, printing, drawing, photo- cciil 53 to· be energized and coil 53 operates a graph or the like. They may be said to consist 10 stylus or other marking mechanism and thus 

of pluralities of spots or elemental parts each of ·message shee~ 4 is reproduced. 

which is either black or white depending upon It will be understood that, whereas the forethe part of the message which it forms. Rela- going description calls for the transmission of a tive movement is provided between lamp l and signal when one only of the coils 14 and 15 is ener- message sheet 4, between lamp 8 and control sheet 15 gized, the apparatus will function just as well and 

6, and between lamp 39 and second control sheet . achieve just as great privacy if rearranged 

38 in any convenient manner heretofore used in slightly, as by giving·an opposite bias, a normal 

the art of facsimile transmission. This causes closed condition, to switch 24-25. In such case, 

the beam of light emitted by each lamp to scan of course, a signal will be transmitted whenever 

every spot or element of the message or control 20· coils 14-15 are in the same condition instead of 

associated with it. In the transmitter this scan- when they are in different conditions. 

ning thus produces a series of impulses in the I claim: 

amplifying circuits through the action of the light 1. Means for secretly transmitting graphic insensitive cells ID and 11. For convenience of de- formation, said means comprising, a message in 

scription, these impulses can be said to be pro- 25 graphic form which it is desired to transmit, a duced by black spots in the message or control. scanner arranged to scan and reproduce said 

Thus coils 14 and 15 are energized every time message as a series of electric impulses of vary- an impulse occurs in the amplifying circuit asso- ing intensity, a screen having varying portions, 

ciated therewith. The action of the relays con- a second scanner arranged to scan and reproduce 

trolled by these coils produces in the circuit asso- :io the variations of ·said screen as a ·second series of 

ciated with them a series of impulses distributed electric impulses of varying intensity,. a relay 

in time as shown in Figure 2 of the drawings in connected under the control of said scanner and 

which the term "X" represents an impulse. This arranged to be moved by each of said impulses 

figure shows the four possible cases. Thus it will to one of two positions, a second relay connected . be seen in column 1 that energizing coil. 14 by a;; under the control of said second scanner and 

message sheet 4 without energizing coil I~ by con- arranged to be moved by each of said second imtrol sheet 6 causes an impulse in the circuit con·· pulses to one of two positions, an electric circuit 

taining coil 23 and labeled "Result" in Figure 2. including parts of said relays and adapted to be 

This energizes coil 23 and causes transmitter 21 closed only when there is instantaneously an imto emit an impulse. As seen in column 2, when 4U pulse in either series but not in the other, a 

both coils 14 and 15 are energized no impulse transmitter connected under the control of said 

appears in the circuit containing coil 23. As seen electric· circuit so as to emit impulses whenever 

in column 3, energizing coil 15 but not energizing said circuit is closed, a receiver arranged to re- coil 14 causes an impulse in the circuit containing ceive the impulses emitted by said transmitter 

coil 23. Column~ shows that when no impulse is 45 and having an output comprising a third series 

present in either amplifier 12 or 13 and, conse- of electrical impulses of varying intensity, a quent!y, neither coil 14 nor· 15 is energized, no second screen duplicating said first mentioned 

impulse appears in the circuit containing coil 23. screen, a third scanner arranged to scan synchroTo put it another way, an impulse only appears nously with the scanning of said second scanner in coil 23 and, therefore, an impulse is only sent 60 and reproduce the variations of said second screen out from transmitter 27, when coils 14 and 15 are as a fourth series of electric impulses of varying 

not in the same condition, i. e., are not simul- intensity, an electromechanical interlock con- taneously energized or de-energized. This is due nected under the control of said third and of said 

to the fact that simultaneous energization or de- fourth series of impulses and arranged to be ener- energization of coils 14 and 15 causes movable 55 gized whenever an impulse occurs in one of said 

contacts 16 and 17 to engage stationary contacts third and fourth series and no impulse occurs 20 and 21, respectively, which are connected to simultaneously in the other of said third and 

the same side or polarity of source 22. fourth series, and a recorder connected under the 

The series of impulses emitted by the output control of said interlock and arranged to operate 

element 28 of transmitter 21 is received by the 60 whenever said interlock is energized and to 

input element 29 of receiver 30. Each impulse thereby reproduce said message. so received energizes coil 31. Motor 35 produces 2. Means for secretly transmitting graphic inrelative movement between second control sheet formation, said means comprising, a message in 

38 and light 39 so that control sheet 38 is scanned graphic form which it is desired to transmit, a 

in synchronism with control sheet 6. Since sec- .

65 scanner arranged to scan and reproduce said mes- ond control sheet 38 is a duplicate of control sheet sage as a series of electric impulses of varying 

&, coil 43 is energized in synchronism with the intensity, a screen having varying portions, a 

energizations of coil 15. Referring again to-Fig- second scanner arranged to scan and rep1'oduce 

ure 2, the line labeled "Result" represents the the variations of said screen as a second series of 

impulses which pass through receiver 30 and ener- .

70 electric impulses of varying intensity, an electrogize coil 31, while the line labeled "Control" repre- mechanical interlock connected under the control 

sents the simultaneous impulses caused by con- of both of said series of impulses and arranged 

trol sheet 38 and which energize coil 43. Figure 2, to be energized whenever an impulse occurs in 

column I, shows that when there is an impulse one of .. said series and does not occur simultanein coil 31 and none in coil 43, an impulse is pro,. .70 ously in the other of said series, a transmitter 
REF ID:A104975 

2,552,648 

5 

connected under the control of said interlock so as to emit impulses whenever said interlock is 

energized, a receiver arranged to receive the impulses emitted by said transmitter and having 

an output comprising a third series of electrical 5 

impulses of varying intensity, a second screen duplicating said first mentioned screen, a third 

scanner arranged to scan synchronously with the 

scanning of said second scanner and reproduce 

the variations of said second screen as a fourth 10 

series of electric impulses of varying intensity, a 

second electro-mechanical interlock connected 

under the control of said third and of said fourth 

series of impulses and arranged to be energized 

whenever an impulse occurs in one of said third 15 

and fourth series and no impulse occurs simultaneously in the other of said third and fourth 

series, and a recorder connected under the control 

of said second interlock and arranged to operate 

whenever said second interlock is energized and 20 

to thereby reproduce said message. 

3. Means for secretly transmitting graphic information, said means comprising, a message in· 

graphic form which it is desired to transmit, a 

scanner arranged to scan and reproduce said 25 

message as a series of electric impulses of varying 

intensity, a screen having varying portions, a 

second scanner arranged to scan and reproduce 

the variations of said screen as a second series 

of electric impulses of varying intensity, a relay 30 

connected under the control of said scanner and 

arranged to be moved by each of said impulses 

to one of two positions, a second relay connected 

under the control of said second scanner and arranged to be moved by each of said second im- 35 

pulses to one of two positions, an electric circuit 

including parts of said relays and adapted to be 

closed only when there is instantaneously an impulse in either series but not in the other, a 

transmitter connected under the control of said 40 

electric circuit so as to emit impulses whenever 

said circuit is closed, a receiver arranged to re- ceive the impulses emitted by said transmitter 

and having an output comprising a third series of 

electrical impulses of varying intensity, a second 45 screen duplicating said first mentioned screen, 

a third scanner arranged to scan synchronously 

with the scanning of said second scanner and 

reproduce the variations of said second screen 

6 

transmitting graphic information, means for 

scanning a message to be transmitted to derive 

therefrom an electric signal irregularly assuming 

a succession of values responsive to the photographic density of the message at the point of 

scanning, means for substantially simultaneously 

scanning a camouflage message to derive a second 

electric signal irregularly assuming a succession 

of values depending upon the photographic density of the camouflage message at the point of 

scanning the second said electric signal being nonsynchronous with the first with respect to the 

variations therein, a switch having two circuitclosing positions, means for causing said switch 

to assume one of its circuit-closing conditions 

when said first-mentioned electric signal assumes 

one value and the other of its circuit-closing conditions when the said first-mentioned signal as- sumes another of its values, a second switch having two circuit-closing conditions, and means for 

controlling said switch respqnsive to said second 

electric signal,' a third switch," a control circuit 

for said third switch said circuit serving to close 

said switch when the first-mentioned two switches are in predetermined circuit-closing positions 

only, and means for transmitting a signal when 

said third switch is in closed condition. 

5. Means for secretly transmitting graphic information comprising a device for scanning a 

message to be transmitted and reproducing said 

message as a series of electric impulses of varying 

intensity, a second device for scanning a camou- flage message and reproducing the same as a 

series of electric impulses of varying intensity the 

impulses of said second series being non-synchronous with the impulses of the said first series, 

a relay connected under the control of said first 

device and arranged to be moved by each of said 

impulses to one of two positions, a second relay 

connected under the control of said second device 

and arranged to be moved by each of the impulses of said second series of said impulses to 

one of two positions, an electric circuit including 

said relays adapted to be closed only when predetermined combinations of closed positions in 

said relays occur simultaneously, and a transmitter connected under the control of said electric 

circuit so as to emit impulses only whenever said 

circuit is closed. 

WILLIAM F. FRIEDMAN. 

REFERENCES CITED 

The following references are of record in the 

file of this patent: 

as a fourth series of electric impulses of varying 50 

intensity, a third relay connected under the con- trol of said third scranner and arranged to be 

moved by each of said impulses of said fourth 

series to one of two positions, a fourth relay 

connected under the control of said receiver and 

arranged to be moved by each of said impulses 55 UNITED STATES PATENTS 

of said third series to one of two positions, an electric circuit including parts of said relays and 

adapted to be closed only when there is instantaneously an impulse in either said third or said 60 fourth series but not in the other, and a recorder 

connected under the control of said circuit and 

arranged to be energized whenever said circuit 

is closed to record the original message. 

4. In an apparatus of the nature described for 65 

Number 

1,310,719 

1,312,574 

1,657,366 

1,763,358 

1,848,839 

1,868,967 

2,300,664 

Name Date 

Vernam ------------ July 22, 1919 Pierce _____________ Aug. 12, 1919 

Belin -------------- Jan. 24, 1928 

Jenkins ----------- June 10, 1930 

Ranger ------------- Mar. 8, 1932 

Cartier ------------ July 26, 1932 

Francis ------------- Nov. 3, 1942