TOP S:CHET 

HISIDRY OF CONVER'IBR M-1.34-C 

VOLUME 2 
REF ID:A523106 

H!S'lURY OF COOERTER M.-134-C 

VOLUME 2 

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REF ID:A523186 

DETAilED TABLE OF CONTENTS 

FOR 

VOLUME 2 

PAGE 

VI CONVERIJ.'ER M-134•••••••••••••••••••••••••••••,•••••••• l 

A. General ••••••••••••••••••••••••••• ~···••••••••••• l 

B. Adoption as St.and.ard .............................. 3 

o. Procurement •••••••••••••••••••••••••••••••••••••• 4 

VII CONVERTER M-l.34-A ••••••• • • ., • •• • ••• • ••••. 111. ~ •• • •••• •. • • 10 

VIII 

A. General •••••••••• • • " • •••••• • ••••• ,. •••••••• -• • • • • • • 10 

a. Procurement ••••••••••••••••••••••••••••• ~········ ll 

c. Description •••••••.•••••••••••••••• ~ ••••••••••••• 15 

D. Keying Instructions •••••••••••••••••••••••••••••• 19 

E. Cryptographic Seeurity .•••••••••.•••••••••••••••. 23 

F. Tape !·lumbering Machine l 90~ • • • • • • • • • • • • • • • • • • • • • • 24 

G. Evaluatio'n •••• • ••••••••• · ••••••.•••••••••••.•.••••• 25 

D~STRlBUTION AND USE OF CONVERTER M-1.34 AND 

M-134-A. •....... • •. ~ • • ........... • ••••••••.•••• • ••••••• • 28 

IX KEYIMG UNIT M-229•···•·•••••••••••••••••••••••••••••· 35 

A. General .......................... , •••••••••••••••• 35 

B. Converter M·229-Tl and its Official Approval, •••• 37 

C. Keying Unit M-229-T2 and Procurement. .............. 40 

D. Cryptogra}llic Funct.ioning ......................... 40 

E. Keying Instructions., •••••••••••••••••••••••••••• 45 

F. Cryptographic Security ••.•••••••••••••••••••••••• 48 

CONVERTER M-134-B (AND OTHER UNADOPTED MODIFICATIONS OF CONVERT.ER Y-lJ4-T2 AND M-134-Tl) •••••••••• 50 

Appendix CHANGES IU KEill4G !N&mUCTIPHS FOR CONVERTER 

M-134, M-134-A 
REF ID:A523186 

LI.ST OF TABS IN VOLUME. 2 

TAB 

A Photograph - ·Converter M.-1341 front view 

B Photograph - Converter M-134, plan view 

C Photograph - Converter M'.""l.34, rear view 

·.O Photograph - Ceyptograph llC-164 of Converter M-l.34J plan new 

E Photograph - Oryptogi-aph U0-164 or Converter M-134; showing 

two cipher discs removed 

'i Photograph - Cryptograph MC-164 of Converter M-134; showing . cipher disc stepping mechanism 

Ci · · Photograph - Converter M-134-A 

H Photograph - Converter M-1.34-A; rear view 

I Photograph - Cryptograph MC-l.64-A of Converter M-134-A; 

plan view1 cover removed 

J Photograph - Cryptograph MC-164-A of Conveter M-134-A; 

plan view, 'l'a.pe Transmit.t.er 110-185 and two rotors removed 

K . Photograph - Crypto graph MC-164-A of Converter M-134-A; 

rotor stepping mecha.nism 

L Photograph - 'typewriter MC-174-A ot Converter M-134-A; showing 

space and carriage return contacts 

M Photograph - Rectifier RA-2.3 

N Photograph .... Rectifier RA-23, cover open 0 Schematic d.iagr>:V.ll ot Convert.er M-134-A 

P Encipher-decipher Reversing Switch of Converter M-134-A 

Q Tape Transmitter MC-185 of Converter U-134-A 

R Cryptograph MC-164-A of Converter M-134 ... A, Wiring Di&graiu 

s· Wiring Diagram of Typewriter MC-174-A or Convert.er M-134-A 

T Photograph - Keying Unit M-229 (short title: SIGOOO), shown 

in place on Cryptograph UC-164-A of Converter M-134-A 

U Photograph - Ke7ing Unit M-229, plan view 

V Photograph - Keying Unit M-229, left stat.or view 

W Photograph - Keying Unit M•229, rear view 

I. Photograph - Keying Unit lf.-2Z9, cover in place 

Y Photograph ... Keying Unit M-229, showing name. plate 

Z Wiring Diagram of Keying Unit 14-229 

AA Signal. Corps Technical Conmittee Meeting No, 146; 

Supplemental Minutes 
REF ID:A523186 

i~P SECIJ R CHAPTER VI 

OOHVER'mR K-134 

for piotographs of Conwner J.it-134, see Tabs A, :B, o, D, E, F. Since 

Converter 11-134 and Converter K-134-A are almost identical, the 

detailed description of both converters is provided onJ.\y with the 

photographs ot Converter M-JJ4-A. For detailed descztiption applicable to both converters, see Tabs G, H, I, J, K, L, M, N, O, P, Q, 

R, s. 

A. General 

Converter ~134 is an electromechanical machine by means ot which 

messages may ~ ~<:iphered up to speeds or about 40 'WOrds per minute. 

Rete:rence to the photographs appearing in Volume l:i Tab Q and Volume 2,, 

Tab A, $how that there~ only two significant differences between the 

final production model, Converter.M~l34 (Vol. 2, Tab A) and the final .. ; .,. " 

~ experimental model; Converter M-l34-T2 (Vol. 1 1 Tab Q). The main differences between the final production model and the final experimental. 

model are (1) the war in which the typewriter and eryptoera.ph are 

assembled and (2) the elimination on the final production model or the 

bank of 26 letter lamps. In the final production model, the two pa.rte 

( ccyptograph. and typewrit,er) are assembled side by sid.e ·and permanent.13 

attached to the base ot the case designed to hold them; ·a copy hol~er, 

located between the t\llO machines, is attached to the base of this ease. 

In accordance with the satisfactory results of the service test 

conducted in November 1936 (see Chapter V, Section D), Converter .M-1.34-T2 

was reconmended for adoption as standard.1 F'rom this time on the 

l. See Section B "Adoption as Starnard", page • 

l 
REF ID:A523186 

experimen~al designation, T2, was dropped, and.the converter became 

lmown as Converter M-134. During 19371 bida for the building of a· 

limited number o! Converters M-134 was received1 and an order tor 

' . 1 

twelve converters was placed. with Wallace and Tiernan Products, Inc. 

These twelve converter$ were delivered. to the Office of the Chief 

Signal Officer in August 1938.1 Minor changes., recomm~mded as a 

result of experience with these twelve models, \vere incorporated into 

the 57 additional models procured. The 57 new models, with changes 

incorporated, became kriown as Converters M.-l.34-A (see Chapter Vll). , 

For an explanation or the cryptographic fWlctioning of Converter 

M-1341 see Chapter V, Section B. The section refeXTed to describes 

the cryptogra}'.:hic .functioning of Converter M-l34-T2, which is crypt.ographically identical to Converter M-1J4. 

For ke1ing instructions, long and short titles,, and classification 

ot the machine,, see Chapter Vll, sect.ion c. The section referred to is 

appμ~~~~ .. ~th t.o Converter .M-134 and M-134-A. The minor dit.t'erences ·I..,~ ... ·• '. - . 

; .. . ·1~·,.. c, :··, '' .,, . 

between the two types a.re .~plained. 

1. See Section C '*Procurement. ~, pages thru • 

2 
/ · 

REF ID:A523186 

B. Adoption aa ·· Standard 

On ll JanWU"T 1937, the Si~ Corps Technical Committee took ·t.wo · . (5ee.1,,.b hA) 

important actions on Converter U-l.34 at its Meeting No. 144. The 

millta17 cbaracteristical of the converter were approved and, actJ.ng 

upon the recommendation of the Chief Signal Officer, "the Committee 

recommended the adoption as to type and olassi.fication as ste..rdard ot 

Converter type u: ... 134°. Disregarding this reco.nmendat.ion of the Si31a.l 

Corps Technical. Committee, on Converter M-134 was instead 

classified by The Adjutant General as a deveJ.opnent type 1

2 limited pro2 ouremant type. 

1. In the Supp~ntetl iliiutes ot Signal Corps Techn.10811 Commit. tee 

Meeting No. 146, 11 Jan 1937, the military characteristics are listed 

a.s follows: · (a) This machine snoul.d be designed for the .f'unclarn~tal purpose ot 

encipherine and deciphering messages with speed, accuracy, a.nd the 

highest degree of cr,vptographic security. Secondarf tQ these characteristics, there should be a minimum number o:r switches, keying eler.i.ents, 

etc., which must be set betore proper operation can begin. 

. (b)· The cryptographic operations should be controlled by an external. 

element. which is variable and is not an intrinsic part. of the mechanism. 

itself 1 such as a perforated tape similar to that eoplo,ed i11 printing 

telegraph apparatus. T!1e underlying cryptographic principle should be 

th.at of a continuous,, non-repeating, unintelligible or random-mixed 

key sequence of characters governing the enciphe:rni.ent of successive 

letters. . le) The roachl.ne should oonsist of two units. (1) A cryptographic 

unit hereinafter ealled the nc:ryptogra.ph", provided with a standard 

typewriter keyboard, and (2} a recording unit suitable for makine a 

printed. record of the work done by the machine, preferably an eleotr1-

call.Y operated typewriter, hereinafter called the 11 typewriter11 • The 

cryptocra.ph is the part of the .mechanis.m 1n which the encipherinr, and 

decipherinc operations occur; the typewriter is electrically associated 

with the cryptograph and is to print the cipner text, in case of 

encipherment, in 5-letter groups, lO groups per line; in the case o:t 

. decipherment, the typewriter is to print the plain text, preferably in 

their oric;inal word lengths with proper spacing between words. 

(d) The· minimura speed of operation should be 30 words per minute• ~e) The cryptoerapb and the typewriter should bo mounted upon the 

For continuation of footnotes see followinz page. 

3 
REF ID:A523186 

c. Procurement 

On l March 19371 OGS1g0 not.i!ied Signal Corps Laboratories of the 

t1'0 actions of SCTC and directed them to procure, in accqrdance with 

Act of May 15, 1936 {Public r~o. 5941 74th Congress), as maJ1T ma.chines as 

the limitation of funds pemitted, '*but not less than eight in any case". 

Continuation of footnote land· rootnote"2 from preceding page~ 

same base with fixed electrical connection between the two units. A 

side-by.;,.s:lde arrangement of' these two unit.a is preferable to a. t.andem 

arrangei:ient., 00 that t.he keiboard of t.he cryptograph a.s well as the 

keyboard ot the ty1Jewriter a.re both imr:lediately in fror1t of the opera.tor. 

(t) 'l'he apparatus should be designed to operate on UO-volt, IJ.C., 

power source. 

{g) The v.ieight. oi' the crryptograph including its ca1 .. eying case allould 

not tlxceed 50 pounds; that o! t.he typewriter includin_:~ its carrying 

case 60 pounds. .i:loth units should. be rugged in construction and capable 

of .-;ithstandine jarring incident to t.ransportat.ion. · 

U-1) The entire assanb.13 should be so constructed that in case the 

typevJriter is out of commission for any reason, cryptographic operations 

may be continued by means or elec'\iric l.iziit-bulb indicators on a lamp 

board. on the cryptosrap.h. \See note below.) 

li) 'l'i1ere Jr.Uat. be incorpo1•ated features to suppress interference 

with radio receivers operated. in the vicinit..r of the machine. 

Note: . The military cbaraoterist.ics, as here quoted, were later 

amended to omit par. J&{l)(h}. \See par. \hJ above). 

2. J.iequired types. - Required types comprise articles of equipment t'or 

which there a.re existing or expected needs and tor which militaey 

aharacteristies have been approved ••.• JJevelopnent types are required 

t.ypes ot equipoont. being developed to meet approved military characteristi~s as follows: 

(a.) Experimental tyj,es ••• 

(b) Service test types ••• 

(c) Limited procurement types comprise articles of equipment which 

have passed service tests favorably but are not ready for 

classification as a.n adopted type and w~1ich before such classification should be subjected to an ext~~ded service test. Tile 

approval a.a to limited procurement type sienii'ies that the itat'l 

is probably- suited for service use but requires refinement in 

deai§Il or f'urther use of hands of troops t.o determine definitely 

its suitability. lrom Aa. SS0-25 1 .30 June 1943, Page S. 

4 
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REF ID:A523186 

..... ~ 

The original proposal for the budget of 1937 included 

119 ,;oo for the purchase of Convwtera ll-1)4. However, . thia allot.ment 

was not included 1n the 1937 Expenditure Program of the Suppl.t Division 

as .finalJ..Y appro~ed. 1 'f'nerefore, diacuasion~, vihich began 1n DeC$Uber 

. 1936 and continued intermittently during tl1e .first two months ot 1937, 

concerned both how the $191 500 of the original budget allotment could 

be redeemed for ~itial procurement andliho should construct the converters. The first proble.:n was solved by trans.terrine $19,500 from 

the Office rteserve.2 

. . 

The second problem of ~ho should construct. the convert.era was solved 

only after a bit of disagreement. It. aeerr.a that "tlle letting of secret 

contract.s ·to a commercial manufacturer was a new concept, allowable under 

the provisions of "Act of May 15 1936 {.PUblic No. 594, 74th Cons:ess", 

a.nd not everyone concerned with the matter waa satisfied that the new 

secret convert,er would be sate with a commercial concern. Much disouaaion 

ensued concerninB the existence of spies in commercial plants. However, 

8.esearch and Development Division of tne Office ot the Giliei' Signal Officer, 

recomm.encled. to the Executive Office that· tkle eaiverter could be beet 

l. liemorandu.m., Act,!Qn 6, l"ronn Fiscal; ToJ Ix~ O., 2/a57Y'/. Folder ), 

ftJ.l ... 134, M•J.34-A, Px;ogurement. l thru 1!40}, CSGAS-80. 

2. Memorandum, Action 9, Prom; Fisca.l;.Oi iu. o., 2/26/37. Folder 3, 'lU-l.34~ M-134-A, frocurement { thru 1940) 1 CSGAS-80. 

' 
~·. 

REF ID:A523186 

manufactured by a commercial oonoern.l Therefore, the deeision of the 

Chief Signal Officer, concurred in by a 0-2 representative, was nt;.o 

negotiate a secret contrac~ with one party, the contract to include 

the wiring of tne wheels 11 •

2 

On 27 lay 19)7, Si{iflal Corps La.bOrato~ies reported to OCSigO that 

a bid ·had been received from Wallace and Tiernan Producte ~ Inc., Belleville,,.»~ J~ to manufacture Convert.era M-134 in lots ot 8 9 $2,310 each, 

total $1.8,480; in lots of lO @ $21 200, tot.al 1221 000; 12 @ $211.35, total 

$25,620. Tne answer from O<JSigO directed that a contract with Wal.lac• 

and Tieman, Inc. be let for S converters and that it ahou:ui provide tor 

an increase 1n quantity in case further funds became ava.lla.ble during 

F. I. 1938.3 

l. Memor'fuidliii, From: MD Division1 To: ii. o.; 2/2/'$/. Fold~r 3, "14-l~, M-1.34-A, Procurement; ~t.hru 1940), C~GAS-SO. 

2.. " •• 3. T'nis Division does not app:reolate the objections 

raised to placing the entire machine with one mnuf'acturer. 

SQL has recently' placed one order for secret apparatus and 

is in process of pl.acing another with nputable commercial 

concerns under the provisions of RAct of Ma.7 15, 1936 

(Public No, 5941 74tll Congress)". The provisions of' this 

act apply equally to commercial manufacturers and to governmental agencies, and it is the opinion of this Division that 

the M-l.34 would be as well safeguarded b~r a reputable commercui concern as it would be by e:ny or the agencies listed 

in basic letter. This Division, therefore, recommends that 

t:1e entire procurement be made from one agency, preferably a 

reputable co.m.raeroial. concern. 

2. Memorandum, Action 11 «aecision of the CSigO and concurred in by G-2 

representative", 2/3/37. Filed in Folder 31 uM-134, M-134-A, f.£2-

curement ( t.hru l2't0) 1 CSGAS-60. 

j. 1st Ind., From: WD OCS!gO, To: SO Labs, 28 May 1947• Folder 3, 

"M-134, U-1:34-A, Procurement. ithru 1940)., CSGAS-80. 

6 -

. 
\ 

·~ 

REF ID:A523186 

The original order was actuallT ma.de tor l2 convert,ers,1 the additional tour being decided upon at the last moment in order to effect a 

saving of 7 .6%. The procurement of the additiona.l four ma.chines d.ecreaaed the unit cost to ~2 135 (as opposed to a unit cost of $2,310 

when ordering 8) and ma.de a grand total for the 12 or $251620 .. 2 The 

$7,140 re(1uired. for the additional .four machines was .forwarded to 

Signal Corps Laboratories under Procurement Authority SC 8412 P5-3059 

A 060~8. 3 The cont.ract number for these l2 converters was W lCY/7-SC443, Order No. SCL .37-1082, date • 

1 The contract we.a fulfilled 

in August 19~ when the 12 converters were shipped to the Off'icer in 

Ctiarge of Signa.1 Intelligence Service, Oi'i'ioe of the Chief Signal Oi'ticer •. 4 

These l2 converters proved aatisf a.ct.ory but experience with them showed 

l. Memorandum, Ex~ ··o: to Fiscal, Action 8, &Approved purchase 12 

machinea 11 ~ · folder 3, "M-lJ4, 14-134-.A, Pr,ocurement ( t.11ru 1940), CSGAS~. · a. The memorandum vihieh discusses increasing the order t.o 12 converters 

ate.tee in Action 3 (Supp4' to R&D, 8/12/.37) that the fla.pproved 

procurement program for P-5 includes $5,000 for the J:'I'OCurement. of 

2 M-l34 1s. This sum can be made available~~," and states in Action 7 

(Fiscal Div. to lt'lt. O., undated} tt1at "the fiscal Division can make 

available the additional ~2.l.40 required in addition to the amount 

set up in the Supply Division Pro8J"8.11l•" Mem.orandura, op. cit. 

3. Ma."'!Orandum, Action 9, Fiscal Div. to R&D t.hru Suppl.J' & WP&T,, 8/14/37. 

Fold.er .3, op. cit.· 

4. Shipping Ticket, Consignor: S.P.o., Signal Corps Laboratories; To: 

Officer in Charge, Signal Intelligence Servioe1 Office of the Chief 

Signal Officer; Aut..."lority: Le OCSigO 413 .. 52 \7-2-38)., Evidentl, 

the 12 converters were retranaported by SC Labs t.o Signal Intelligence Service from the manufacturer. 

7 
REF ID:A523186 

the desirability of minor cb.anges1 in any new zdels procured, The 

incorporation of these minor changes into the next and all additional 

models procured resulted in the new desia;no.t.ion tor them: Converter 

M-134-A. (For a discussion ot the di.fferences between Converters M-l.34 

and M-134-A, see page • For a diacu.ssion of the reason for the ditferences,, see page 

l. Letter, Subject: Converter M-l.34, Toa Director, Sigial Corps Laboratories; From: Louis B. Bender, Lt. Col., Signal Corps, By order ot 

the Chief' Signal Officer, 19 Sept 19;8 • 

• • • 2. The following changes, wl1ioh have been found desirable as 

a. result of experience with the twelve converters purchased last 7ear, 

sbould be included in the new converters: 

a. The sbeels ot the five plugs connecting to jack strip should 

be engraved with the numbers l,2,J,4, and 5 respectively. It is also 

desired tha. t sixty extra. plug shells suitabl.1' engraved be fumished 

this of fic.e for installation in the old converters. 

b. T.'le connectors &o the plugs should be approxim.lltely two inches 

longer and made of more fiexible wire. 

c. Dispense t1ith the apertures in the lid which covers the rotor 

assembly of the cryptogra:ph and cut a large rectangular opening in 

the lid so that the entire rotor assanbl.y including the stators will 

be exposed to view. . d. The numbers engraved on rotors 6 mid 9 should be clifte:rentiated 

to preclude the possibility ot misreading. It, is suggested that .B.onan 

numerals mia,ht be engraved. on these two rotors aboVe the Arabic 

numerals. 

e. The copy holder should be removed entirely from t.he base of tile 

machine and ma.de a separate item. It should also be made tilt.able 1..111 

order tna.t the operator may tilt the ®PY' holder to suit his convenience. 

t. ·r:.-1e right and left ·margin stops on t.he typelU'iter should be provided with set screws with hexagonal. heads and hexagonal locknuts to 

prevent stops from working loose. 

B• The margin release should be rendered inoperative. It is 

suggested that tbls could be done by inoert.ing a washer between the 

typewriter frame and the removable ma.rgin rel.ease button. It is 

desired t.~at twelve washers be furnished this office £or installation 

on the old machines. 

h. The top cover plate of the tape transmitter, wilch is non 

black, should be made approximately t.he sa.rue color as the unfinished 

metal ot the rest ot the transmitter top. 

For continuation ot footnote see following page. 

a 
REF ID :A523186 -

Continuation of footnote 1 .from preceding page. 

3. 'l'h• followine changes are also deairable and should be 

made it 1t. can be done without necessit.at1ne any appreoiable delay 

or involvinJ any major changes in design. This mat.ter is. left to ~he discretion of your Labora.tori,s. a~ The warnin:_; bell on the typewriter is not l.oud enouzh to 

insure that. tlie operator will hear it at all times. 1£ it eannot 

be made louder, it. is suggested that Jtmigiit be advisable to convert t!1e present pilot lamp on the or-1ptograph into a warning signal 

for the operator. There seems to be no necessity tor the neon glow 

lrunp to indicate that the .motor is runninr,. 

b. It, 1a rather difficult to remove and pepla.ce tile lid ot' Case 

CS-54 wi t.~1out. exerting t.oo much pressure. It would seem ad.vi.sable 

to modify the case to l.'>U1ke the removal of the lid less difficult. 

c. ·The IBM typewriter is usually equipped with a stroke counter. 

'lhis would be usetul addition to t.he 11 .... 134, inas.ouch a.a it would 

enable a Check t.o be ma.de of the number of keys struck on the 

ccypto5ro.ph and tbe number or operations of tile typewriter. It l'lOuld 

be especially useful in deeipherina. 

lst Ind., WD, OCSigO, Wash. Nov, 17, 19,38. To: Director ot SC Labs. 

The to~owinr;:; instruct.ions are given in reply to basic letter: 

a, Jqur. .. ·~posa.l for t.he purchase of 10 converters M-134 is approved ... tJ)::(,!8,pt; 

(1J Uo stroke eounter'.1 are desired.. 

{2) ~ many of t.he mcditications listed in attached letter dated. r~av. 14, 1938 from Wallace and Tieman as you. consider 

practicable .si1ould be included. 

b. ·The cost of the ele'ctrical registers .mentioned in par. 2 and of 

t.:1e extra 60 engraved plug shells in conside?'ed excessive. They should not be purchased.~ 

e. Twenty•two copy bolder•~ Rite-Line with ion eye r,uide are 

4es1.re<.t. They should, however, be purchased. on a non-secret basis. 

d. The removal of t;19 copy holder troo t.he maelline will elimina.t.e the 

trouble ment.ioned in paragraph 3b of our letter of Sept. 19, 1938. 

The trouble men t.ioned, therefore, should be disregarded.. 

l:iy order ot the Chief' Signal Uf'tiQer: 

9 

H. P. Browning, 

U&jor, SJ..cnal Cprps. 
REF ID:A523186 

For phot.ograp~ls and detailed description, see 'fabs G, H, l 1 J, K, L, . a, N, o, P, Q, R, S •. 

A. General 

Converter U.-1.34-A is a .modification of Converter .1-1,34. After the 

delivery by t.he manufacturer in AUol".1\lst 1938 of the i'irst twelve Con- . 

verters i.t-1341 experience with these converters suggest.ad xn.l92r improvements1 which were incorporated into all suc;cee<ling models. The more 

obvious ot these improVG1.{/f$.Oit:J wore (l) addition ot the rotor-releaoe 

lever, 2 (2) addition 0£ a slow-operate relay,3 (.3) the cutting of a ..ell 

1n the lid just above the rotors,4 and (4) the removal of the copy holder 

trom the base ot the case for issue as a separate itEJJl. Allmcdels a.ft.er ' . --..'. ~ ~ -., . . 

the fil"st·l.2 contained these ~hanges $nd were designated as Convert.era 

J4•134·A~ Between Deeanber 1938 and .May 19421 57 Converters ~l.34-A were 

procured according to the schedulo outlined 1n Section B, 8Procurement8 • 

1. For ll$t. Qf the changes suggested in Lett.e:r, Subjeeti Cooverte:r ii-134, 

Tot Director, Si[.;11a.l Corps Laboratories, Signeds Louis B. Bender, 

Lt. Col., s.o., by Order ot the Chief Signal Officer, 19.Sept. 1938,, 

see footnote , page • 

2. Rotor-release lever. (Compare photograph of Converter M-134, Tab A 

with photograph of, Converter U:-134-A; 'tab G.) T~1is lever 1 included. 

only on Cryptograph 164-A is mounted on the left of the rotor asst,tinbly, 

in front. of the plug and jack st.rip. By pulling forward on this lever 

the rotors are disengaged from all pawls and are free to be turned in 

either directiono Rotors of Converter M-134 can be turned only 

toward th~ front. 

3. Slow-operate relay. - The function of this relay is to hold the rotor 

stepping solenoids energized tor a sui'iicie.nt length 0£ time t.o 

insure oorJ.plete pluger travel and subsequently to clear the circuit. 

to tae normal open state. 

4. Well cut in lid just above roto:rs. Compare Tabs A and G. This well 

in conjunction witn the rotor-release lever perm.its insertion and 

removal. of ro~or~ without removing the lid. 

lO 
REF ID:A523186 

r:: ' .. , 

lr~~ B. Prgcurement 

The aecond procurement of Converters M-134, with th$ changes 

which mad• them Converters M·lJ4.•A (see pe.ge tor dU'ferences), was 

ot 10 converters obtainable with ia;,0001 allotted to Signal. Corps 

Laboratories for the purpose. The actual cost of the 10 machines was 

$231850.00.2 'l'hq •re obtained on Contra.ct W l07rf-SC-'Jl7, Order· 

' 3 

SOL 39-771, 13 Dec. 1938, with Wallace and Tiernan Products, Inc. This 

order for 10 converters waa completed l April 1940. 

In 1939, l2 more Converters M-l.)4-A were ordered from. Wallace and 

Tieman, Inc. ® $21 .385•00 eaCh, total $28,620. In procurement of Converters M-134 and M-134-A, the associated equi~ent or spare part.a was 

almost as big an it.em as the converters t.hemselves. The original a.,Uotm.ent to SC Labs for the 1939 p:roourement of 12 converters was ~ .. 300.00, 

only '28,620 of which VBS used for converters. The remainder was all 

l. Lett.er,, Subjects Converter ii-134, 'foa l'hreotor, SI;lil Corps Laboratories; From• Le>.~~ Bl! Bender, Lt. Col., s.c., 19 Sept. 1938. 

"Funds in the ~o.~~ ot' $251 000 are being allotted to your Laboratories 

for the procur~~ ~£ 'ten, (lO) Converters lt-134 and Sp!Lre parts." 

z, Memore.ndwn1 Action l, Toi Suppq Division, R&D Division, Signed: 

s.B.A, 13 Sept 1939+ " ••• Contract W l077"'3C...317 ••• calls tor 10 ~chines at a total c:ost or· $23,8.50.00~ q" Folder J, Jl-1)4., M-134-A, 

Prgcurement ltpru 19t,.O), OSGAS-SO. . 3. iimo, Subject: Shipnent (If Convert•ra M-134; fo; Director, SC Laboratories,, From Louis B. Bender, COl. s.a., By order of the CSO:o 

1.3 Oct. 19.39. " ••• Contra¢t Ho, 'ii lC1/7-SO-Jl7, tμe SCL 39 .... 7711 

elated Dec. 13, 1938· 

ll 
REF ID :A52318.6 

CONTRACT DATA 

Converter ll-134; M-134-A 

.(over) 

*The contract information given in the chart 

can be completed. only by discovering the contracts. The total cost. of the ce11verters - proper a.re not the same a.s the total cost of 

the contra.Qt because ma.l\V' contracts contain · orders tor rotors and other parts 'Viiich cost &a 

m.ueh a.s the converters themselves. {See 

footnote » page J Therefore, to llst the · cost ot the converters 1 which are the onl3 

numbers g1 ven in the M-l.34 folders, is to 

present a distorted picture. ' 
· 1st Purchase 

u ... 134 

2nd Purchase 

lt-l.34-A 

.3rd. Purchase 

:cll-134-A ·-·--.-·'' 

5th Purchase 

~134-A 

6th Purchase 

. M-134-.A. 

) 

··REF ID :A523186 

l2 

10 

l2 

Wallace & Tieman 

Products, Inc. 

Wallace & Tiernan 

Products, Inc. 

I 

Wallace & Tieman 

Products, Inc. 

Wallace & Tieman 

Products, Inc. 

lO Wallace & Tiernan 

Products, Inc .. 

S wall.ace & Tiernan 

Products, Inc. 

COnv.ERT.IR M-134; Jl-l,3/,.-A 

Procurement* (See text al.so) 

Contract \'i 1077-SC-243 

Order SCL .37-1082 

Contract W 1077-SC-Jl.7 

Order Sci:. 39-771 

13 Dee 1938 

Contract W-1077-SC-355 

Order 706Siqt-4.0 

l Nov 39 

Contract W-1077...SC-443 

Order 799...SCL-41 

The last l2 converters built under 

this contract were modified according 

to ci1ange to Contra.ct W 1(1'/7-SC-443, 

3 Oct 1940.. Of the l2 modified converters, the first 4 wre dif'terently 

wired: the connections to the left 

and right st.ators were changed and 

4 sets of secret and contidential 

roto.r.s were differently 'Wired.. The 

wiring in the 4 converters and 4 

rotor sets were changed tor special State Dept. use. · 

Contract W-1077-SC-1474 

Order 13.321-SCL-42 

25 May 1942 

Contract W .22Sl-SC-126 

Order 1224-SCGDL-43 ~8 July 1943 

) 

«see £ootnote on reverse 

side of this page. 

Completed; 

2 Aug 19.38 

1Apr1940 

15-23 Oct. 

''·1940 

&ir. Nos. 

l -12 

l,) .. 22 

:-·-. -~ 

- . -. ~~~·; 

3~ - ~--' _:_::~) '.i) -;.,31 -- --·· --..... _ .. 

51 - 60 

61- 68 

\ ) 
,---;;-....._ 

REF ID:A523186 

spent for spare part.s. l The SC Labs were direcied on l6 Sept. l9J9 

by OOSigO to procure these 12 .conv-erters from Wall.ace and Tieman 

Products, Inc.2 The contract for these 12 converters was Contract. No. 

W 1077-SC-3551 Order 706-SCL-l+Ot l Nov. 19)9• . '!'bey were delivered 

l2-2;; Oot.ober 1940. 

I. 2nd Ind., ii)~ &sliO; 'lo: Dlrect.or,·sc Labs, 17 Oct,. 19~9: 

1. It is desired. ~at. ~e following equipnent be procured trom 

Walla.Ce & Tie~an Pro,4~g~~.f Inc.,, Belleville, .N,J. b,y secret. contract; ' ' 

" 992tit.z Total Cost Item,. 

l2 Conver~ M-134 • f213s5.oo ea. 128,626.oo. 

14 Sets or Tool.a @ 16.oo ea. 22,4.00 

10 Slow pμU-up "1a.y with 

ill!.droa.djustment @ 7.;o ea. 75.00 

l4 S.ta of 3 fuses • .45 ea., 6.30 

l4 Sets of keyboard contact 

springs t 2,70 ea .. 'J?,80 

24 Sets ot 3 insulated mov-

&bl• key contacts . • l.6; ea. 39.6e 

2lt. Green top micro switch 

with spring plunger • l • .35 ea • 32.-40 

24 ;O...Ohm suppressor resistor @ ,35 ea. B,40 

21+ o.; mtd.· euppresaor 

condenser I .so ea. 19.20 

24 l mtd. oil-filled supressor condenser @ 1"10 ea.. 26.40 

10 . .. Modified tape transmitter @ 139.75 ea.. i,397.;o 

24.·.: ._:,·<~bar sol~oid with- ., , . · .: ' out plunger @ ll.40 ea. 273.60 

10 End stator complete without engraving\a) @ 61.25 ea. 612.~ 

·J.0 Intermediate stator, 

complete (s.) • 51,10 ea. 51.L,OO 

10 Lot of 50 stator 

springs (b) • 3.00 et.l • 30.00 

10 Lot of 50 gold·pla.t$d bronze stator contact 

balls (b) @ 5,00 ea. 50.00 

6 Set of stat.or assemblf 

clamps le) @ 24.70 ea.. 148.20 

for cm t.inuation or tootnotes see following pag~ .• 

13 
REF ID:A523186 

Continuation ot tootnotes from preceding page. 

l 

l 

Item 

- Set of S spring contact.a 

tor tape transmitter 

connecting block 

Eleotrana.tic typewritQr, complete as modif'ied 

for Converter M-134 

Cryptograph frame, including keyboard contacts, 

reversing switch less 

tape transmitter and 

rotor stepping mechanism 

Rotors comple-tel.v assembled 

but with wires soldered 

only to one side (as per Wallace and Tiernan quota- . tion 0£ Sept 22, 1939 

@. 2.00 ea. 

® 1,000.00 _ea. 

ft 1,000,00 ea. 

Total Coat 

48.00 

1,000.00 

9,860.00 

2. lt ia also desired that 12 Rectifiers RA-23 for 60 cycle operation,, complete, and 60 spare Tubes EL-6C be puroha.sed.. · ,3. funds in the amount of $481 30().00 are being furnished 

your labo:rat.ories for this purpose. Since the eost 0£ some of 

these items are only e st.imat.ed, this a.mount. may not be aui'ficient. 

lf not, adjustment will be made upon notifica.tion of the additional. 

a.m.ount required. 

2. Letter, Subject: Purc;hase of Converter M-134; To; Director~ SO 

Laboratories, 16 Sept 1939. Procurement Folder. 
-~ 

, ' 

Two more contracts tor Converters K·l34-A were let to Wallace and 

Tiernan Products, Inc.: Contract No, W lr:l'f'l-SC-1474. (Order No. l332l-SCir 

42) dated 25 lay 1942 for 10 oonverters and Contract No, w 228l-$C-l.26 

{Order No. l224-SCGDlr4J) dated lS July 1942 for 8 converters. 

The ~ont.racta here d1aou111sed aocount for o. total order.of l2 Converters M•l.34 and 56 Converters K~lJ4~A, WlkinG a. grand total or 68.1 

c. nescription 

For det.a.iled description, see Tabs G, H, I, J, K, L, M, M, o; P, Q, R, S. 

When Converter M-134 vra.s issued, offioia.J. long and short titles 

were assigned to the various main parts of the machine for more efficient. 

acaoun,ing purposes and to better distinguish between the SECRET a.1'1.d 

2· unolassif ied parts. 'l'be Converter M-134 com.prises two r.iai..'1 oom.ponen ts, . ' 

namely, Cryptogra.ph MC-1643 lsee Tab A) snd Typewriter MC-1744 (see Tab A). 

VJ'nen the second. order .for t,he machines was placed with the m:muf'act.urer 

and minor changes were incorp<>rated (see page ) , the distinguishine ·· 

tit.le, Converter M-lJ4-A5 was assigned to the whole assembly and the 

... · .... ; ( ; 'i '1 

lti Mr. Cond.e;rfs dist;ri,tiμt,ion t?iures give the tot.al as 57 aonver£ers 

K-1:34-A and therefore ··a. grand total ot 69, instead of 68, co1werters .. 

2.. Nomenola.tun, Gonver-ter 14 ... 134, assigned by Nomenclature Section, 

OCSigO,,.on 28 Uov 19.32. _ 31 Nomenclature, 017ptogaph JIC-1641 aasigne4 b)r Nomenclature Section, 

OOSigO, on 17 April 1937· · 4. .Nomenclat.ure, Typewriter 110-1?4,, assigned tw Momenolat.u.re Section, 

OCSigO 1 on 17 April 1937. 

5. Nomenelature, Convert.erM.-l.34-A_.. assigned by llomenolatu:rcJ Section, 

OCSig(), ~n 8 Nov 1939~ 

15 
·~ 

,~, 

il 

~. ' .. ·~· !l ,_\ -'; :_ 

' r 

t! ~-- ):.: L! 

titles, Oryptograpb MO-l64-A1 and Y.C-l74-A2 were assigned to the two 

chief components. 

Cubic 

VJidt.h Deetn Height. Di§> la.cement 

a. In operation, lounted on 

Cr.yptograph Ma.;..1641 l4i" 16" 11!" One Base 

7.4• 

b. ln ope rat.ion, Electric 

Typewriter MC-174; l?~· 1611 9 3/4" 

c .. Packed in carrying 

case: 37i" 22~· 15" 7.4• 

Weight 

a.. In operation_, Cl""JPtograph IJC-164: .35 lbs. 

b. In operation, Electric 'lypatlll"iter Mc..;.1741 43 lbs. 

c. Packed in earryinr; case t 160 lb$. 

Three other long iiitles were assigned. t.o parts of the Cowerter 

M-134,; M-l.34•A.. These were Copyholder litC-184 llater MC-184-A), Tape 

Transmitter MC-185 \later MC-185-A) and. Oe.se CS 543 (UJ.ter CS 54-A).4 

In addition to the above named. lone titles, t:.he following short 

t.i tles were ~signed to the various it.ems pertaining t.o Converter u-1341 

l. iliomencle.ture, Cryptogt"aph :uc-lbt-A, ass!giied by '1'iomancliture Sect.Ion, 

OOSigO, on 9 Nov 19)9. · 2. Nomenclature, Typewriter MC-174-A, .assigned by Nomenclature Section~ 

OCSigO, on 8 Nov. 193<). . .). ~lomenclature, CS-54,, assigned b1 I~omenel.e.ture Se?tion, OOSigO, on 

17 April 1971. 

4. Nomenclature, CS""54-A, assigned by lfomenclature Section, OCS1g01 on 

9 Mov. 1939. 

16 

J~? ~Er 
Cryptograpil ~l.64 \exclus1V$ ot rotora) ••••••••••••••.••••••••• SIGT!P 

Rotors SG-14 {ind! vidual rotors indicated by arabic · . 

numeral after short titlo) •••••••••••••••••••••••••••••••••••• SlGT.ER 

Rotors SG-15 { indi.vid.Ual rotor~ indicated by arab:ic 

numeral after short title),•••••·•••••••••••••••••••••••••••••SIGLIG 

Set 0£ key tapes (individual tapes to be indicated by 

are.bio numerals a.ft.er short. tit.le) .............................. SIGREP 

While the converter assembly less oryptograpll and rotors \ SIGTUK) 

is SECRET bees.use t.he assembly as a whole gives an indication of the 

f\mctioning of the converter, t.he individual units suoh as the Typewriter 

MC-174, Copyholder MC-184, Tape transmitter MC-l.85, a.nd·Case CS.-54 ere 

wiolaseitied when removed fr<>m the converter assembly. 

The tu.net.ions of the two main componenhu, Oryptograph MC-164 and 

/-- Typewriter MC-174, are as follows: Vfuen. the cryptograph has been properly 

prepared acoo~g to keying instructions and the encipher-decipher switch 

ha.a been placed in the EHClPHER position, strikine the iceys of the key-

~rd ot Cryptograph M0.164 1n accordance with the in.di vidual Characters 

ot .the plain-text message results in the production by Typewriter M0-174 

of a printed, unintelligible cryptogram spaced in 5-letter groups. Conversely, by setting the apparatus to the earo.e.ket'used in eneipherinc 

and plac.ing tile encipher-decipher tmitch in the DECIPHER position~. this 

c~rptogram may be deeirJ.lered by striking the keya on the keybQurd of the 

Ccyptograpll 14.C-l.64 in accordance with the individual printed characters 

ot the cryptogram, whereupon the typewriter prints the original plainte.."Ct message in _pormal word lengths. 

l.7 
REF ID:A523186 

Typewriter llC-174 ma:s- aleo be operated directly in tn>ing the 

plain-text parts ot messages, such as addresses a.nd s:igna tures, message 

reference numbera,.dated, indiee.tors,, etc. For this operation the 

enoipher-doeipher switch is placed at DECIPHER. In order to transmit .,, 

to its destination the cryptogram produced by Converter li-l.341 it. is 

necessary to employ one of the conventional means of communication 

such as wire or radio. 

The teaturea or eneipherment which provide cryptographic security 

are described in the chapter on Converter ll-;t34-'l'2 (Ohapter V, Section B). 

Aco0rding to the first operatine instructions issued: Converter 

M-134 wa.$ provided. with 10 rotors (SIGTER rotors). This number of rot.ors 

issued pre~iled until .April l.940 men. t~ new ;\instruct.ions proVided 

that the number of rotors issued would be 15.. Five of the 15 rotors provided were red.-colo~ed and lO gray-colored., The new red-eolored rotors, 

consiat.ine of the set of 5; bore the short title: SI.GLIG. The two types, 

red (SIGLIG) and E#a.:J (SIGTER) were issued in order to provlde dif'.ferent. · 

rotors for Secret and for Confidential messages. The five red SIGLIG 

rotors were used tor Confidential messages only. The ten grrq S.IGTER 

rotors were used for Se.c:ret. messages only. This method of using t.wo 

sets o! rotors prev<?..iled for a.bout. a yea.r~ In March 1942, new keying 

, instructions were published which provided that 15 rotors v;ould be issued 

with each machine but that these 15 rotors would constitute one set. 

'I':1e old rod and gray rotors were still used 'but the ol.d distinction 

between them was el.i.tli."£Q.ted. 

lS 

ID? SECll 
REF ID:A523186 

The documents oontaJ.111.n,g the operating instructions tor Converter 

ll-134; :M-l.34....A are as follows: 

"Operati."lg Instructions for Converter M-134u, (short title: 

(SlGQUG), September 19.)8. . 

"Opera.tine Instruct.ions tor Converters .M-lJ4 and M-134-A", 

(short title; SIGKOC), JuJ,y 1, 1940. 

"Suppl.ement to Operating Instructions for Converters M.-1)4 am 

M-l34•Au, (Photographs and Drawings of Converter M-134-A.), 

(short title: SIGVYJ), July 1, 1940. 

Associated documents: 

"Parts Tape· Transmitter and Auto Control Relay Unit", Telety-pe 

Corporation Bullet.in t~o. 10181 December 19.30" 

"Description and Adjustments of the 'l'ape Transmitter«, Teletype 

Corporation Bullet.in Mo. 103 (Issue 2), October 1938. 

D. Kuing Instructions 

The documents containing the keying instructions for Converters 

M-l.3.4e.nd M-1.34-A are a.s follows: (An outline of the changes occurring 

through the yea.rs in the keying instructions is given in Appendix I,) 

"Keying Instructions for Converter 1-134", (short title: SlQl>UF)» 

Sept. 1938. 

"Keying Jnatructione !or Converters M-134 and li-l,34-Alt; (short 

title: SlGJU.X), April, 1940. · 

"Keying Instru.ctions !or Converters M-l.34 and M-l.34-A", (short 

title: SIGLOG)' Marcil 1942. . 

Keying instruetions f'or the Converter li!-134; M-134-A are as follows: 

Convert.er M-l.34; ii...'i-134-A employs five keying elements, two which are 

changed at the beginm.nr; of each ~ and two which are changed with 

19 
REF ID:A523186 

mt? ~m~H every mQSaage. The t.wo dail.1 k911ng elements a.re lll the rot.or a.esem.blg, 

by which is meant the selection and arrangement. of rotors •. and (2) the 

selection of t.he key tape to be uGed for the daq'. The three L.lessa.ge 

keying ele1r~cnts are (l) the variation of the connect.ions between the 

s•nsine pins of the ta.pa transmitter and the rotor stepping magnet$, 

which variation :1.$ a.ccor:ipli$hed by changing th.e orde1 .. of' the plugs in 

the ja¢ks of t'..'1e plu,z and jack st.rip.}. ( 2) the initial alignment of t..hti 

rot.ors,; (J) t.i:ie initial. posit.:\.Qn Qt the ~Y tape. 

T'ne rotox- assom.bly (or· ttelection and an-ar1goment of rotors) ia 

accomplished at the beginnint;. of ea.on day by means of the current. rot.or 

assembly tabla o.r tUla system. for u:arAple, if the table shOWI that for 

January l the rotor assembly i~ 8-'J-l-.9•7, it metm:J rotor B is irulierted 

in position l, rotor 3 in position 2, etc. 'l'he arra.ngem.ont is .made from 

le£t to right., The first instructions published in September 1938 provide 

that a set of 10 rotors be issued with each machine. ·T~e superseding 

inst.ructions of April 1940 provide for 15 ro:-.ors: 5 red re.tors to be 

used for Confidential meaaages and lO gray rotors to be used for Secret 

meaaaGGS e Tha superseding instructions of M.a.rch 1944 st..ill pr<>T.i.de for 

' 15 rotors but, contrary to the use prescribed in the April 1940 instru.otions,, these 15 rotors constitute one set.1 

111 lfKeY?iig Instructions for COnverter ii-134° and M-l.34-A", (short t.ible: 

SlGLOG) I Uarch 1942~ ltfhe red-colored rotors heretofo:::-e used for 

confidential syste!IW are no longer to be used as such; all 15 rotors 

eon:;Jtitute one set. · The 10 gray-... oolored rotors are identified by 

arabic numerals (except numbers 6 and 9 whic'l are raraan), the redeolored rot.ors are identified by roman numerals, precoded. by the 

ltt.t.er C. These d.Uf'erences will serve to dU'f'el"Elrltiate a.ll the 

15 rotors of the set., :tof' keying purposes. n 

20 
REF ID:A523186 

The key tape to be ua~d tor the day is selected as follows: A 

elet of numbered t.a.pes is issued with each K-134 system. To select. the 

tape to be used fQr the 4aj<, the tape numbers are used in conjunction 

w.ith the current Key Tape Selection Table of the system. For e.Y..ample, 

the table may show that on.January l the tape to be used is 17. According to the September 1938 and the April 1940 keying instructions, each 

set of key tapes issued with a Converter M-1.34 system consists of 48 

numbered tapes issued in duplicate. The duplicate copies are explained 

a.s being merely reserve editions tor use in ease one OO?Y of the tape 

became damaged. The superseding keying instructions of March 1942 

provides for a. ebange in t.he policy of issuing ta.pa aet.s as follows: 

~ne $et. of 48 tapes, !urnislled 1n duplicate, for each Secret M.-l.34 system 

and one set of 30 tapes, furnished in triplicate, for each Confidential 

M-l.34 system. 

The variation, with every mess8.ce, of the connections between the 

sensing pins of the tape transmitter and the rotor stepping .rr.agnets 

is _accomplished by changing the order of the plugs in the jacks of 

the pl.ug and jack st.rip. The order of t.he plugs in the jacks is deter-· 

mined before eneipherment of every .o.essage as follows: An indicator consisting of live letters is chosen !! random by the operator., Suppose 

the group selected by t.he operator is FHBGR. These letters are ~signed. 

numbers in aecorda.nce with their relative order in the normal. alphabet 

thus: 

f-H-B-G-R 

2-4-1-3-5 

21 
REF ID:A523186 

Theae numbers determine the order.of the plugs in tbe jacks. (For 

detail1 eee Chapter V, Sect.ion B, page ). For the next message a 

new indicator is eeleoted a.t, random and the order is again derived 1n 

the $8ID.8 ~. 

The initial alignment of the 5 rotors is accomplished before' the 

encipherment of every message as .follows; Tho same five letters as was 

selected to detGrmine the order ot the plugs in the Jacks are used. 

Using t.he same example \see above), tho indica.t.or selected at. random 

by th$ operator was FHBGR. The operator aligns the rotors by hand 

indiv1d.ual.J¥ to the randoml,y-choaen indicator group, in this case, 

... a!$~g FHBGR on. the bench mark from left to.right • . - ,,, :'."""' . '·~ .. :.- ... , 

· 'fne initial. p0sition ot the key tape is derived ae follows: EV$ry 

tenth Ba.udot- character or eacn key tape-is numbered by a large number 1n 

whit.e ink. To det~e.the initial position, the middle l letters of 

' . - the Sa.me 5 letters previously chosep ~ indicator (see above), are used. r ,, . 

The value of the middle 3 letters is found by re!erring to the current 

table of the system. This table is called "Table for. Determining Initial 

Position of Ke,y Tape". It is merely· a table which assigns a numerical • I ' • 

value to eaoh letter of the alphabet. For example, using the letters 

FHOOR and a Position of Key Tape Table 'Which gives the following. values 

!or tho middle three letterst H :s 81 B = 2., G = 7, the key tape-would 

be set a.t the bench mark of the tape transmitter. The method here 

described Wa.s pr$Scribed both in the September 1938 keying instruction• 

and in the April 1940 keying instruct.ions. 'l'he keying instructions 

22 
REF ID:A523186 

·published in llal'Ch 1942· modified this procedure as follows: For 

Secret messages, the lst, 2nd.~ and 3rd lettera of the indicator are 

us•d.; for Confidential mossages, the 2nd, Jrd1 and 4th letters; tor 

aestricted messages, the 3rd,; 4th, and ;th letters .. 

All keying instructionsproVided for a. ma.x1mum numbeJ" of groups 

of cipher. text which could be enciphered with the ~ame oessage keying 

elements.l ln the September 1938 instructions, the r..ia.x.imum length 

was 50 to 60 ·5-letter groups. In the September 1940 and lfarch 1942 

instructions, the m.axh:lm length was 100 5-letter groups·. 

~. :<;.mtoara@c Secyit;y;; 

Convert.or M-.1;34-A was an advanced. ertptographic ·machine tor its 

day and had great potentials for s~ty. However, the indio.o.t.or system 

and the makeup and use of the key tapes rendered the machine vulnerable 

to cryptanalytic at~ck. With a secure indicator system and careful 

tape m.akeup with one-time use, the machine would have ha.d more security 

than Converter ~l.34-C. The security of the machine as it. was used ~ 

dependent on the following: 

l ... tiie rule Iii the inetruct.ionaI documents was worded as follow11 

"lf' t.he cr,yptographed text of a meoaage' will exceed 50 to 60 

{later 100) 5 ... ietter groups, the plain t~t. will first be divided 

into two or more approximately equal pal"ts and each part will be 

treated as a separate message. 

2. This cryptographic security evaluation is cQpied. from 1•1!istorical. 

and Cryptologic Summary of Cryptoayatems", Volume I, (short title: 

ASA0-2.3). 

23 
REF ID:A523186 

At lea.at lO messages in dtpth or a large sinount of pertect~ 

matched plain and cipher text. from sev•i-al messages in one classitioation 

are necessary befo~ the endpla.tes, rotors, and ke1 tape can all b$ reconat;ructtct. In general, less material would be needed than for reoonstruQtion of Converter U-134...C roto:rs. Since t.ha ta~s were made up so 

that the levels were all nearly random, ea.ch rotor G~pped approximately 

SO% ot the time ancl thereby pr()duced lliAl13' lob$tera, delayed lobsters l' and 

partial lobaters. These lobsters constituted an opening wedge for an 

attack. 

With matched plain and <::!~r text., the number o! exhaust.ive trials 

necessary to ident.ify known rotors is large, but 11ot so large as to be 

imp:raQt.ical. · There ·~ io x 9 x a x 7 x 6 l"otor arrangements tor the 

, SECRET classification. and ; x 4 x 3 x 2 x 1 rotor 13.rl'angenents for tae 

CONFIDENTIAL clasaificat.ion. For each of these, .3l pt)ssible motions 

must be assumed between enoipherm.ents. With the iuentifillation of the 

rotors, the key tape is recovered as messages are read. 

\~it.h known key tapes as well as knovin rotors, the number cf 

extiaustive trials eqUals 10 x 9 x 8 x 7 x 6 x 48 for the SECRET classification and ; x 4 x 3 x 2 x l x 30 for the CONFIDENTIAL olassif ica.tion. 

f. ;tpe B91Perinfii Machine .u.-120 

So that the·operatore of Convert.er M-134; M-l.34-A could locate 

on t.he keying tape the exact tive...unit eode group with which.the 

encipherment of a mssa.ge began, it was necessary t.he.t the tapEJ be 

24 

1~P&f1 
REF ID:A523186 

marked. To accomplish this ond,1 a project tor developnent of an 

automatic key-tape marld.n3 devie• wae. begun in Augu.st 1937 •

1 The work 

was done at Signal C<>rps Laboratoriea, using as a basis for the develop-. 

mant 110rk, "an old model of the tape marking device made by the Laboratories several years be.tore.nl The m.odel wa~ .completed by Signal Corps 

Laboratoria about June 19.38. In k.y 19.)S, the following nomenolature 

2 

was asaigned1 Tape Numbering Machine M-190. 

A brief description of Tape Numbering Machine :M-190 £ollows:3 

The tape numbering ma.chine opera.tea trom llO volts a.c.; 60 cycles, or 

llO volts <1.e. to number a nve-unit-oode tape .rrom O to 9991 every ten 

holes of the tape, A universal. motor drives a transmission and cam system 

to, aut~t,ica.UY adVance the tape ev•il'Y tenth-hole position, depress, 

.• i~ia\e:, and advanqe the numbGr-p;'1nt1ng wheel$, and teed a typemter 

ribbon bet~ th• prinUng wheels "'1d the tape. The over-all aiz• ot 

t.he machine is approx1.'!l4toly S in. by l.3 1n. by 5 in. and the l!flldght 

about 96 pounds. . . 

G,.. Evaluation 

Converters M•l'.34 and M-134 ... A have a h1gh security val.ue and a low 

operational value. The inventor, Ur. Friedman, realized very early that 

l. iAtter, Subject; Automatic !ey• Tapti Lrking Device; foa JSirect.or, s~c. Labs; From1 Louis s. Bender, Lt. Col. s.c.; Aug. 27, 1937• 

folder 111 Converter M-134J M·l.34-AJ' Associated !gaj.pnt. 

2. lat Ind., Fr00t WD, OCS1g0; fo:i Director, s.c. Laba; 21.Mar 193$. 

Folder ll,. Converter K-134J U-134-AJ Associated !s~nt • 

.3• Let.tar, Subject; Request for Nomenclature; To; CSO~rom• Lt. Col. 

Van Duesen, Lt. Col., s.o., 19May19,38 •. Folder ll, :U-134; M·l34•A; 

Associated !g,uipnt. 
tape control would. require critical adjustments, poasibl.7 necessitating 

frequent ael"'licing. Th•refore, when Mr. Frank B, Rowlett conceived., 

· about June 1935, a n.ovel idea tor controlling rotor stepping in simulated. 

randan fashion by sending an electrical impulse through the circuits of 

a roto:r mo.ze, it was soon recognized b;r Mr. Friedman and Mr. Rowlett a.s . . 

opera.tiona.J.13' superior to the key-tape control currently under considera-

. . l 

tion, Mr. hiedm.a.n helped Mr. Rowlett. to Q.evelop his fortunate idea 

and · together the7 urged t,he Cl1ief Si~ Officer t.o convert the preproduction model of Gonv•rter M•l34-i'21 then being constru.cted1 to t.he nn 

type of rot.or stepping control. However, the Chief Sien.al Officer was 

oe>mmitted to the type being eurrentl.v bU:ilt into the preproduction model 

~£ Converter ll-l.34-'f2 (key tape control) and couJ,d not be persu~d to 

make any chan;.,"&. T'nerefore,, 68 Converters ll-131+; M-134-A were built. ./ 

It required actual oparo.tional. experience w1 th the new converters to 

contirm the original bslief of the inventors in the practicability of 

aband.onine tape control in favor of the Friedman-Rowlett concept. of 

l control by means o! an electrical. current through t.'16 circuits of a 

rotor maze to generate a long, irregular sequence oi' eharacter:;J. 

The Friedma.n...Rowlett concept1 found e~:pression in a.,, astonishing 

manner. The Chief Sicna.l Officer, ha.Ying· ref~ed to adapt Converters 

M-1341 gave Mr. Friedm~.n permission to di3close the new, una.dopted 

i. P'atent Application 70,4121 Medm&n and Lwlettt filed Lrch 23, 

1936. This pa.tent is still under a Patent Otfice Secrecy order. 

Conceived about June 151. 19.3.5· 
~F .'.ID :A523186 

,·:.:· .. ,·, ... · · .. -..;: ., .·· 

.. ~ ~ .· .. 

·.:.·.· ... ·.·. ' . .'· 

. .-.. _, .. _·_. · .. ·.-': -.::-. _ ... __ 
·~REF- ID-:A523186 

principle to tht Nav,y. Th• Ilav•s developoont of the idea to produce 

the converter which is the main subjeQt of this history (Nav;y ECK Mark II 

or·~ Converter,M-134-C) is explained in Chapter XI. ArJI\V orders 

for the new Converters ll-lJl+-C began .in. June 1940. Even · though a few 

more Conve:tt.ers u:...134-A. were o:-dered after tbie date (to a total of 6a) 

Converters ll-134-C ~oon took preced.enoe. 

·.·By~ l94l the operational inefficiency of tape control of the 

enciphering ;rotors of.Converter M-JJ4,,·i-134-A had been sufficiently 

demonstrated ao that the Chief Signal Officer not onl\r agreed to 

ordering Converters ll-l,34-C in quantit;.y but; a~o agreed to an &daptation 

of the existing Converters M-1341 u..134 ... A by rn.ea.ns of a keying unit, 

called l_{ey'ing Unit M-229. Ke1ing Unit M-229 is one of the possible 

~ variations of the Friedman .... Rowlett c0ncept1 of control by an electrical 

current through the circuit.a or a. rot.or maze. Its development. and 

description are presented in Chapter U. 

For dist.ribut.ion and use of the· 6S Comrert.ers M-134 and M-134-A,, 

see Chapter VIII. · 

27 
REF.ID:A523186 

CHAPTER VIU. DISTRIBUTION AND USE OF 

CONVERTER M-134 AND CONVERmR M-l34•A 

OnJ.Y 68 Conve~ers M-1.34 and 14•134-A were manufactured. Since 

the basis of 1ssu~· was two converters per establishment, it is imn.ediately apparent that_ these conv•rters did not attain very wide usage. 

The distri~ution plan for ConverterM"'."l~ {d.:ra.wn up in 1937) called 

for supplying the General. Staff, the Air Force General Headqum-ters, 

eaoh Corps Are~ ~d. Department Headquarters, and the Signal Corps 

Training School. Even this limited distribution plan did not get off 

t.o a very fast start, for dell vary or the machines by the manufacturer 

·was .. slow in addition to the fa.et that the orders were placed in mere 

dribbles. The first ·order !or 12 raach~es -was delivered 2 August 1938, 

the second order for 10 machines was delivered l April 1940, the third 

order for 12 ma.chines was delivered between 15-23 October 1940. Another 

16 converters were ordered in the summer of 1940 l delivery date unknown) 

and the last 18 were ordered as late as the summ.o:r of 1942 ldelivery 

date unknom). 

The just-listed scheduled. orders and <teliveries shows that from 

:.igust 1938 until l·April 1940, onl.y 12 converters were in exist.ence. 

f'ne first five of these 12 converters were escorted to their destination 

by their inventor, William F. Friedna.n, in order to insure proper installation and adequate instruction in their operation. The inventor~ who 

left New York with the converters on 15 November 19.)S (USAT Republic) 

28 
ID:A523186 

delivered two t.o the .Panama Canal Department, Quarry Heights J one 

to the 9th Corps Area, Presidio ot San Fr~cisco; and two to the 

H~~ailan Department at Honolulu. The remainder of the first l2 ware 

delivered within the next several months to the Porto Riean Department, 

The Phillipine Department and the 8th ·corps Area. One was held by the 

War Department Message Center. Experience with these 12 converters 

provided the basis .fol" the changes which ma.de the next order, Converters M-1.)4.-A. The dir'eetive for incorporation of the changes is 

probably partially responsible for the considerable dela.y in delivery 

of the $econd order. 

The second order ot 10 converters arrived in Washington on l April 

1940. Distribution of these 10 converters introduces an interestins 

/---- aspeet ot general cryptographic hi.l;ltory, namely, the beginning of the 

modem type code room or what later beeair:..e known as the cqpt.ocenter. 

On 5 April, letters were sent to the Sigial Otfice:rs of t.he lst, 2nd, 

.3rd, 4th, 5th, 6th, and 7th Corps,Area.$ and to the Commanding Ofi'icer,, 

General Headquarters, La.ngle1 Field, Virginia eta.ting that within the 

next month one Convert;er M-l.34-A would be issued to them. T'nese .. 

future recipients ot the Convert.er were instructed to pr•ovide secure 

'storage space of sufficient size that the Converter could be operated 

with the spice. The delivery schedule of shipment within tbe month 

was not met because the Corps Areas immediately answered the statements 

29 
REF ID:A523186 

iDf ~ffiE t~at suitable storage spacel was not available for housing the converter• 

Never before had there been issued a large electrical machine which 

could be seen only by authorized operating personnel and., in addition, 

wa:s such a large and delica.te a mechanism that it could not be moved 

around. Therefore, these new factors caused the scheduled recipients 

o:f the converter to .spend the next few months in makin& ready .for the 

new code rooms. It was necessary that each room have onl,y one entrance 

and that;. the d\>ors, windows, and possibly ceiling and floor be covered 

by a grid system so that a.or attempt to enter the room by unauthorized 

persons ahould set off a burglar ala.rm. It was also considered highly 

desirable that the vault be of fireproof construction throughout. By 

the time sa.tisf a.ctory rooma -were completed,. the aurnmer of 1940 had gone 

by; the converters were actually shipped in August and September. 

The third order for 12 machines (deliv-ered 15-2.3 October 1940) were 

distributed in two ways: (l) t.o inerea.se by one the number of machines 

held by the Porto Rican Department, tb.e HawaUam Dep~ent, the Panama 

Canal Department, and the 4th Corps Area and (2) t.o establish a special 

London-Washington circuit between' the tJ.S.M.A., London and the War 

Department Message Center. 

l,. This problem or secure storage.space within which the· converter could 

be operated did not come up until the second shipment simply because 

no one seemed to realize that it would take so lone to provide it. 

The recipients of the first order were notified of the necessity for 

tr1is type of storage space but the shipments oce~red so eoon after- . ward that it is probable that the first eonvert~s were -housed under 

improper conditions tor the first few months of their installation. t~ \' 

~ 
REF ID:A523186 

J~~ ~BG~H ln order to establish this special Washington-liondon circuit, four . . 

converters {Reg. Nos. 2.31 24, 25, 26) were specially wired1 by SC Labs. 

The connections to the left and right stators were ~hanged and .four sets 

ot secret rotors and four sets of confidential rotors were differently 

wired. TWo of these s:r;ecially wired machines were held by .ES.A, London 

and two by the wmtC. On Aug. 6, 1941 the YA London requested2 a third 

convert.er. He gave two reasons for his request. First, the traffic 

handled by the tl10 machines was heavy. Secondly, since the code rooms 

of the State Department, Arm,v, and Navy were all located within fifty 

feet of each other in the Embassy at 1 Grovesnor Square and therefore 

a.ll three were in constant danger of being destroyed by a single bomb, 

it was advanced that a third Wlit should be placed in the new bomb-p~oof 

shelter being built at 20 Grovesnor Square, one room of which was to be 

a code room, This request was approved. but delivery was delayed until 

• T'ne "delay was due to slowness of delivery by the manufacturer who \Vas having dif'f'i.cUlty obtaining.sane of the needed material.a.3 

This reque~t was eventually answered with Convertel's M-134-A, register 

nos. 49 and 50. 

It is unnecessary to describe the distribu t:ion of the remainder of 

i 

the Converters M-134-A in detail for the following list of original and 

1'inal holders completes an adequate outline or the distribution of 

Converters M-l.34, M-1)4-A. 

l. fiie .rewiring was being accanplished about October 1940. 

2. This letter from MA, London was writteq to AC of S, G-2. 

3. Letter, for AC of s, G-2 from 0., K. Sadtler, Col., s.c., 27 Aug. l94l. 

Folder 13, London Circuit. 

Jl 
JORE? ~ffliH Converter M-134 

Reg. No. Original Holder Final Disl?,2aal. 

1 Puerto Rican Department Destroyed 

2 WI> MC Destroyed 

3 Panama Canal DeISrtment. Destroyed 

4 Panama Canal Department Musewn 

; 9th Corps Area Destroyed 

6 8th Corps Area Destroyed . 7 Puerto Rican Department Destroyed 

a Destroyed 

9 Hawaiian Department Destroyed 

lO Hawaiian Department Destroyed 

11 Philippine Dei>artment Destroyed 

12 Philippine Department Destroyed 

13 2nd Corps Area Destroyed 

lA 6th Corps Area Destroyed 

15 GHQ Air Force Destroyed 

16 2nd Corps Area Destroyed 

17 W D Lil C Destroyed 

l.S .3rd Corps Area Destroyed 

19 .5th Corps Area Destroyed 

20 ?th Corps Area Destroyed /~ 21 .. lst Corps Area Museum 

22 4th Corps Area Destroyed 

2.3 USM A London Destroyed 

'-!+ USM A London Destroyed 

g; W-D MC Destroyed 

26 WDMC Destroyed 

Zl Panama. Canal Destroyed 

28 lla.waiian Department Destroyed 

29 Philippine Department Destroyed 

30 4th Corpe Area Destroyed 

:31 WDMC Destroyed :;2 2nd Air Force Destroyed . 

33 Ha.waila.n Department Destroyed 

34 Philippine Department Destroyed 3; Jrcl Corps Area Destroyed 

36 WDMC Destroyed 

37 Wright Field Destroyed 

.38 7th Corps Area Destroyed 

!. 
~. 

Reg. No. 

39 

40 

41 

42 

43 

44 

45 

46 

47 

. 4S 

49 

so 

51 ;2 

53 

54 

55 

56 

57 

58 

59 

6o 

61 

62 

63 

64 

65 

66 

67 

68. 

71 

ID:A523186 

Originaj. Holder 

State Department. {Bought) Stat$ .Department (Bought) 

State i>epartment (Bought) 

Sta.te Department. (~ught) 

WDMC 

Puerto Rican Depirtment 

G H Q Air Force 

,Major Doud . Hawaiian Department 

Hawaiian Department 

ti S M A London 

USM A London 

State Department {Bought.) 

State Department (Bo~t) 

State Department (Bougjlt) 

State Department (Bought) 

S S U, Secy of War 

MIDPAC 

S S u, Secy of War 

S S U, Secy of Wai~ 

U S HQ Calcutta 

U S HQ Calcutta 

We.rehouse 

h'arehouse 

Warehouse 

Warehouse 

)10th Bomb \'ling 

310th Bomb Wing 

3loth Bomb Wing 

310th Bomb Wing 

Air Force 

Final Disposal 

Destro Destroyed ye~ Destroyed 

Destroyed 

Destroyed 

Destroyed 

Destroyed 

Destroyed 

Destroyed 

Destroyed 

Destroyed 

DeGtroyed 

Destroyed~ Destroyed 

Destroyed 

Destroyed 

Destroyed 

Destroyed 

Destroyed 

Destroyed 

Destroyed 

Destroyed 

Destroyed 

Destroyed 

Destroyed 

Destroyed 

Destroyed 

Dest.royed 

Destroyed 

Destroyed 

Destroyed 

(~uobers 69 and 70 were apparentlJ' never noticed as being skipped, There were onlj' 69 SIGMIC1s manufacturer and No. 71 aioove should have 

been assigned the number 69.) 

l. Memorandum for the Chief', ASA, from L .• tiv. Parke, USN, Chief'> Division 

of C.ryptographT, S i'iia.roh 1948. Filed: Folder l, Converters U-134, 

Y-134-A (general), CSGAS-SO. "Reference is made to 1our letter ••• 

requesting intor1nation relative to t.he dispositi9ll or eight. SIGMYC ••• 

devices~.. The SlGMYC devices have been eryptograpaically destroyed; 

the ciphering units have been dismantled and the typewriters are 

being used for other purposes." 
REF ID :A523186_ 

KEYING l>EVIoE Jl-229 (SIGGOO) 

75 units manui'a.et.ured. These were assigned Register Numbers 2 • 76, 

omitting No. l. 

Of these 7~ unit.a, 

No.-18 is in the Museum 

35 was destroyed 7 sold to State Department; subsequently d.estroyed 1 

13 sold to State Department; subsequently destroyed l4 sold to Stat.e J;)epart.ment; wbsequently destroyed 15 sold to State Dopart:nent; subsequently destroyed 

42 sold to State Depa.rt.men t; subsequently· destroyed 

54 sold to State Depa.rtmen t; subsequently destroyed 

58 sold to State Department; aubsequent.ly destroyed 

67 sold to State Depa.rtrnan t; subsequently destroyed 

The remaindf,}r are now all in th,e t'Jarohouse. 

l.. llemorandum for the c:1ie.f 1 ASA, trom L. w. Parke,· u.sN ,' Chief, 

l>iviaion of Cryptography, S March 1948-. Filed: Folder 1, Converters M-134, li:I-l.34-A (Gener-al), CSGAS-80. "Reference is ma.de to 

.vour letter ••• requesting information relative to the disposition 

of ... eiliht SIGGOO dev.lces ••• The SIGGOO devices ilave been ccyptogra.phica.ll,y destroyed 'by complete disassembly". 
REF ID :A5231-86 

CHAPTER IX. HEYING UNIT K-229 

For photographs of Keying Unit M-229 1 see Tabs T, U, V, w, X, Y, z. 

A. General 

Keying Unit M-229 consists of a sinel,e unit of three rotors in 

cascade through wllieh electrical circuits are passed to produce a 

lengthy disarraneed sequence of keying charactAJrs for controlling the 

permutations 0£ the rotors of Converters ·M-134 and M-134-A. It. is or 

such a nature that it can be slipped into the same position as that 

occupied by the tnpe transmitter. (See Tab T for photograph ot Keying 

Unit M-229 in place. Compare with Tab G which shows tape transmitter 

in place. ) The w;q in which Keying Unit U-229 controls the enciphering rotors of Converter M-134 or Converter M-134-A is explained in 

Section D. 

The principle involved in Keying Unit M-229 was conceived by 

Mr~ Frank B. Rowlett in' June 1935 during the interval when preproduction 

models ot Converter M-l34-T2 were. bein.g built. Mr. WilUam F. Friedman 

and Mr. Rowlett developed the idea. together and urged its adoption. 

However, the Chief Signal 0ffic;er. wa~ c~t~ed tQ the type (tape control) 

embodied in the model of Convert~r M~l.34~T2 currently being built and 

he coUld not be persuaded that a. change was advisable. Therefore,, 

development of Converter M•l34 continued, ~Bing ta.~ contro1.. Sixtyei@t models 0:£ this type were cont;Jtructed. 

It was not until experience in eperation of the convert.~rs confirmed ' . ' . ' . ~··. . .. 

the original belief of the inventors in the high security value and low 

JS 

, 

;.: j 

'j' / 

. ' / 

'/ 
REF ID:A523186 

operational value of Con•rtera M-134, M-l.34-A that the new method ot 

controlling its rotors was given oonsidera.t.ion. Wh•n it. was .finally 

decided, in June 1941, t.o adapt the 68 converter1a ll-134, it.134 .... A t.o 

the new type control bf means ot Keying Unit M-229, the Mavy had alrea~ 

. · ~ F'Y'i~ni4ft-"'Riwlt1f' 

shown to the~ their own mechanical and electrical embodiment of the,. 

principle in a con-.erter which they called ECM Mark II (later Army Converter M-134-C). ; When,· in 1935, Mr. Friedman and Mr. Rowlett were unable 

to persuade the A'rm3' to change to the new-type control of enciphering 

rotiors,1 Kr. Friedman obtained permission (see Chapter XI) to disalose 

the idea to the Navy. The first time t.ha.t 9.01one in_th.e Arm:r !mew that 

the "Friedman-Rowlett stepping maze", disclosed by Mr. Friedman iil 1935, 

had been used by the Navy was on Februaey 3, 1940 when Admiral Noyes of 

the Navy invited Friedman, Rowlett, and other signal corps personnel to 

-) . . 

see their new model. 1 {See Chapter n .. ) 

The reason that the use of the concept of the "Frieana.n-Rowlett 

steppine maze" to produce the ECM: Mark ll (or Converter M-134-C) is 

imp0rt.ant. in a 4iscuasion of Keying Unit .M..-229 is because both Keying 

. Unit •-229 and the stepp~g maze ot 0QnVert~ M.-l.34-C are variations of 

the same concept• co.noeive<l by RQwlett in 19,351 and ~eveloped by Rowlett 

and Friedman~ 2 T'ne ~FrJ.edman~ett. stepping maze" was conceived in 

l.. The change desired was from. control of the stepping of the encipher:.. 

ing rotors by means of a Baudot-cod.e tape to control of t.he stepping 

of enciphering rotors by means ot electrical circuits passed tJlrough 

a series of rotors in cascade to produce a lengthy disarranged 

sequence of keying characters. 

2. Patent Application Ho. 70;412, Friedman and Rowlett, filed March 23; 

1936. This patent is under a Pa.tent Ot:rioe Secrecy Order. See also 

Chapter XI. 
REF ID:A523186 

IOf ~HUE ,several variations in June 1935 and, as mentioned in the preceding 

para.graph, revealed to the .Navy. Nothing was done a.bout it in the Arm:r 

until f'ive years later whtn the NayY surprised Signal Corps personnel 

with a mod<ril which used the basic pr1nc1ples disclosed. t.o them by 

Friedman. It. was onl.¥ att.er all this M.d occurred that Si£11al Intelligence 

Service was able to convince the Chief Signal Officer 9f the ef'iicacy 

of the new type control over tape control.~~·~pon presentation o! the 

ECM Mark II by the r~a.vy, the Army imm.ediatols switched its orders to 

Converters M-134-C~ { It was after Oonvertere M-l.)4...C had begun to be . . . 

ordere<t in quantity. that Keying Units M-229 were ordered for t.he purpose 

0£ converting Converters M-134, .M·l.34-A to a. variation or the same type 

r-otors as ~al control of its encipheringAa • r er used in Converter M-134 ... c. 

B. Converter M-229-'fl and Its. Of!icia.l Al?JID?Val 

On 9 May 1941, SiLJl&l. Intelligence Service wrote to t:a.r Plans and 

TrainJ.ng Division that the tape transmitter of Converters M-134 and 

M-134-A "appears t.o require a very critical. adjustment for satisfactory 

operation, necessitat.es·frequent servicing and causes numerous errors and 

d.el.a.ys in moving eneiphered traffic~ It has also b•en found that. the 

production., distribution, and handling or key tape$ presents dit ficulties ••• ti 

Inspired by these considerations, Signal Intelligence Service,, using the 

limited. shop facilities and personnel availa.ble, constructed an experimental 

keying mechanism (la.ter to be oalled Keying Unit M-229-n) whioll consisted 

of a single unit. or three rotors thruμgh which electrical circuits were 

J7 
,/~ 

REF ID:A523186 

IOP 1m_....,,.a 

paS$ed t.o produce a le:-1gthy disarranged sequence of keying characters 

f'or controlling the pormut.e.tions. of the rotors of Converter M-1.34 and 

M•134•A. The new experimental keying unit was built f'rom existing 

elements and spa.re parts of Conwrt.ers U-1.34 and M-134-A~ It. required 

no modit'ie.a.tion of t.he existing converters ex~pt very minor . ones w~dch 

could be accomplished by tha personnel a.t the.using stat.ions. 

The eY.istence, purpose, and advantages of the new Keying Unit iil..:229-Tl 

were made known to War Plans and Tra.ininB Division by its oric;in.ator,, 

Signal Intelligence Service, on 9 May' 1941 by means of' a Routing and Work 

S?ieet. This R & W ,eco!fJ!lGnded the immediate procurement. of t.he keying 

unit and ma.de the following specific requests: 

(1) 

(2) 

(.3) 

(4) 

(5) 

T!.1at the keying unit he considered as a required type. 

. T~1at a. type number be assigned. 

T2'1a.t tho military characteristics accompa.nyin13 the a & W 

be approved. 

'?hat a project be set up for the development or a·k~ing 

unit having the required military characteristioa. 

That consideration be given to t.he adoption of this keying 

unit as a standard article of use by t.he S!Glal Corps as a 

new type of equipment to be used interchangeably with tne 

preser,t tape trans.'llitter tor converters type ¥-1.34 and M-134-A. 

(6) That tt1e subject equiP8ent and all matters perta.1ning tQ its 

development:., standardization., and contemplated use be placed 

in the secret ola.ssification. 

':Jar Plans a..fld Tra.inine Division gave quick approv.ll (10 May 1941) to 

the submitt.inc of tl1e military characteristics to the Si{Ylal Corps Technical Com.it.tee. But· it. did not coneur ·in t,he request that the new keying 
unit be adoptecl as a. required type. It reco.nmended instead that "a 

sufficient number o! service teat models be ma.nuf aotured and turned 

over to the various arm.a and services for service tests • 

. In spite of the fa~t that.all the original recommendations of Signal 

Intelligence Service were not, followed to the lett~r, the processing of 

' the .new keying unit (according to the regulations outlined in AR 850.-25 

for new equipment) occurred in record. time. In 26 May 1941, at its 

meetine; No, 19.3, the Si@la.l Corpa Technical Com.TJ.ttee recommended that 

the militar,y cha.raeteristics,1 as drawn up by the Signal Intelligence 

Service, be adopted. It further recommended that a project be se~ up · 

£or the developnent and procurement of one pilot. mode1, the project to 

be claeai.fied as SEQsgT. On June 14, 194.l, the Nomenclature Section of 

Supply Division, OCSigO, ass~ed t.o the new equipnent. the nomenclature, 

Keying Unit.t type M-229" 

l. 1J1litary bl1aracteristicsa 

l. This apparatus to be designed tor the funciao.enta.l purpose of 

control.ling the stepping of the crypt.ograJiiic rotors of the Converters 

"1-134-( } in an irregular manner, ao as to perform the saLte :functions 

as the present tape transniitter when used on the Converters 1~134-( ), 

but without eraploying key tapes. 

2. The apparatus to consist of a single,unit., comprising a set 

of three control. rotors in cascase, through which electrical circuits 

are passed to produce a lengthy disarranged sequence of keying characters tor controlling the stepping of the crypt,ogra.phie rotors., The 

three control rotors are to be driven by solenoid stepping mechanisms 

identical in type with those now used in Converters M-134- ( ) • The 

order of steppin5 of t.he three control ro.tors of t~1e keyine unit to be 

variable by means of a 6-po~t gane switch or similar device. 

3. The apparatus to be capable of being used .interchangeably with the present. tape tranam.itter used ~ith Converter M-134-t ) and 

to fit. in the position now occupied by the present taP' transmitter, 

preferably without necessitating re-design of' the present cover case 

for Converter M-134-( } • 4~ The keying unit itself to be enclosed within a suitable houaint;t, with apertures for th1:. insertion and setting ot the three control /~ rotors. 

39 
REF ID:A523186 

o. ConvertereM-2&2-T2 and Procurement. 

. l 

Accordingly, the Signal Corps Laboratories •re in.atructed to 

initiate action for the procurement of one pilot model from Wallace 

and Tiernan Products, Inc. Wallace and Tieman, Inc. did their wOl"k 

of developing a pilot model directl.7 on the model built by Signal 

Intelligence Service. The Corporation notitied the Chief Signal Otticer 

Qn. 25 March 1942 that their modification of the oodel was complete. 

Thie modi.tied preproduction model was known as Keying Unit. M-229-T2. 

It was produced by W:allaoe and Tiernan, Inc. on Contract. No. lfY'/7-sc-776. 

The model was inspected and accepted by the Office of the Chief Signal 

Ofticer on 27 March 191+2. Immediately thereafter an order v.ae placed 

with Ylallace and Tieman, Inc. tor 75 Keyi.na Units M-229 (Cost.: Approx-

• 

imately 1450.00 each). The contract. number for this order of 75 unit.a 

. 2 

wre delivered by Wallace and Tieman during August and November, 1942. 

D. .cq:e.to.~apbic FunctiOn.ing 

Keyer M:-.229 (short. tit;le1 SIGGOO) consists 0£ a single unit. (Tab T), 

comprisine a ;>et of three control rotors in cascade, through which electrical circuits are pasaed to produce a. lengthy disarranged seriea of keying 

characters tor controlling the stepping ot the .five ceyptograpllic rotors 

i. Letter, Subjectf · Xqer for Converter M-1.34, To: Director, Signal. Corps LaboratorieeJ From: Hugh·Mitchell, Lt. Col., s.c. (By order 

of the Chief Signal otf'icor), 26 May 1941. 

2. Delivery; 15 units; Aug, 24, 1942; 20 units: Sept. 241 1942; 20 

uni.ten Oct. 241 1942; 20 units: Nov. 24, 1942. · 
REF ID_:A523186 

.,., . 

of M-134; M-134-A. Ke7.-r M-229 ccnsista of twe distinct main parts: 

These two pa.rte are {l) the small rot.or bank, comprising the set 0£ 

three control rotors in cascade (see Tab tJ)1 aod {2} the control multiswitch (aee Tab u, W}2 and its associated stepping solenoids. The. 

functions o! t.:1ese two parts of the keyer difi'er as follows• , The 

· tunction of the small rotor bank is to control the stepping of the· five 

cipher rot.ors of the M-l.J4J M-1)4-A.. The function ot th.e control multiswitch is to provide a variation in the stepping of t.he control rotors of 

the small rotor bank. The manner . in which the control rotors of the small 

rotor bank of Keying Unit M-229 carrr out their function of stepping the 

cipher rot!)r~ ~~ qonverter M-l.341 u .... 134 ... A is explained in the paragraJha 

immediately following. The manner ;in. mich the emtrol rot.or themselves 

step is explained directly thereafter. 

The small rotor bank of Keying Unit; M-229 consists of three randomly 

wired rotors which act as switching eQmmutators bet.ween two end plates or 

stators, Each time a let.tier of the keyboard of Converter M•l.34; M-l.34-A 

is depressed, five circuits are established through the control rotor maze 

·(the three rotors ot Keying Unit ?i-229). The direction Of the current is 

trom. t.he righ.t end plate, through the rotor ma2:e, to the left end plate, 

to the stepping li.la.gnet.s of the five rotors of the Converter M-1J4J M-134-A. 

The entire purpose or these five cireuits t.hrough the control rotor maze, is 

to step the rotors of the Converter M-134; M-l.34-A in random fashion. 

l. The rotors themselves are shown only inTa.b T •. All other pictures show 

the rot.or bank without. the rotors. 

2. Control multi-switch can be located by means of notine small plate 

containing the nurrrbers l, 2, 31 41 5t 6 and a switeil with pointer. 
REF ID:A523186. 

The exact manner in which the control rotor maze of !eying Unit 

Jl-229 effects stepping <>f the tive rotors ot the Convert.er ll-l.34 

(M.-134 ... A) can be beat understood by exa.min:lng the ~nc in detail.' 

On th.e right·sta.tor of Keying Unit K-229, there a.re five entrance 

•Pots tor the cmTent which become "alive" each -time a ke;r o:r the oonverter keybi:mrd iG depressed. Since t.here are 26 contact points on the 

sides of each rotor, there a.re 26 numbered entrance points 0n the right. 

~~tor (see Tab U) out all ot.t.hese entrance points a.re "dead" except ···'':''' 

five~ The five "live~ entranoe points {a.a the ley-ing Unit is presentl.3' 

wired) a.re oontact points.16, 20, 26, 3, 10. {These numbers, 161 20, 

26, ~. lO~ appear on the Wiring Die.gram, Tab z, designating the five 

"liven entrance point$ on the riBht. stator. In 'l'ab u, some of the wires 

ean be seen attached. to th.ese five designated entrance points on t..~e 

ri~t atator.· The cunent enters the right. stat.or at these five "live" 

spe>ts and. thereby eBtabllshes fl v& paths through the control rotor .maze.) 

From here on, ea~"l of the f'i ve paths o.f current est.abllshed is through 

ti'le alphabet maze in. normal tashion,l that. is, directly through the 

stator to the touchine contact on the left face of ~he tirijt rotor, to the 

contact, to whiQh it is wired. on the right ra.oe of the first rotor, and on 

through the control rotot· maze in. this manner (see diagram. on Page ) 

to the touching contact on the right end plate or stator$ 

The le.ft end plat,e <;>r stator (T'tb V) of Keying Unit .1 ... 229 e~taina 

26 cont.a.ct points. n1e contact points a.re banded or wired together in 

l. For description of the path of a current ~hrough an ~lpbab~t maze. 

see diagram, page 
REF ID:A523186 

groups as follows: Cont.a.ct pointi 7i a, 91 10 and ll are wirec:l t.oget.iler 

in $UOh a. ~ that if one of the circuits through the control rotor maze 

. . l ends in any one of these contact points, it will cause rotor no. l of 

the Converter M•l34J 1·134-A to step. (These five contact points, ?, s, 

9, 10, ll, a.re d•signated. on the Wiring Diagram, Tab z, by the letter A. 

'lhe wire can be followed on the Wiring Diagram,, Tab z, .fran the banded 

contact points designated by A directJ.y to the stepping solenoid 0£ 

l ' 

rotor No. l of Converter M-l.34.) In the same 1ialf, contact Points lJ, 

141 151 and 16 are \-:ired together (designated on Wir.L"lg Diagram, Tab z,, . l 

by the letter B) and affect t.he stepping Of rotor no, 2, Contact 

points 21 31 41 5 are wired together and control rotor np. 3.1 Contact 

point$ 18, 19, 20, 211 22 a.re wired t.ogether and control rot.or no. 4~ 1 

Cont.act points 231 24, 25, 26 are tdr~d. together and control rotor no. s.1 

Contact point no. l of tile right stator is a dtad end; lt is wired to 

nothing. 

To better show the ettect. o! the five circuits thro ugil the control 

rotor maze on the stepping ot the c1phar roto!'s 1 an example i& given. 

Suppose that the current enters at the fl.Ye "live" spots, 16, 20,, 26, ;3, 

10 on the left stator \which is ·an invariable C)ircumstance of every 

encipherment) and leaves the control maze at the exit points, 18, 7, 20, 

l, 22 (which points are varied by the variable pe.th through tne control 

l. fhis bandLig of contacts can be switched as a unit by th& operator 

t.o control instead any of the other four rotors. This switc.'ling is 

accomplif'Jhed_by means of the plu,g and jack strip or Cony-erter M-134; M•l34-A. . 
REF ID:A523186 

ID?~RJ~H rotor me.ze caused by the stepping of the control rotors.1 According 

to ti1e Wiring lliagram, Tab Z: 

Exit P,Oint lS. (Group D) cauees rotor 4 to step. 

hit point 7 (Group A) causes rotor l to step. 

Exit. Point. 20 (Group D) c&U$eS r0t.or 4 to step. 

Exit. point l (Dead end) ...... • ........... •• •••.•• 

Exit point 22 (Group D) ea.uses rotor 4 to step. 

Therei'ore, the effect of the five circuits or the example ie thnt 

two rotoro1 rot.or l and rotor 4, of Converter M-134; ti-134-A step with 

this particular encipher-aaent of a letter • 

. The control ;rotors of Keying Unit. U-229 step as follows; One of the 

·throe rotors is a fast-stepping rotor which· steps each time a letter is 

enciphered. A second rot.or steps once each t.ioe the fast stepping rotor 

has stepped 26 times. A third ro~or steps once each time the medium 

~ stopping ~tor has stepped 26 times., T'!lis atepping is aceo.Jl,.ullshed by 

mea.na of steppin,:; solenoids beneath the rotors, the e~gizine contacts 

tor which are controlled by the control multi-switch \Tab u, Tabs U and V)2 

located at t.he right of the keying unit~ 

'file function ot the control multi-Switcl~: is to vary the· positions 

of the fast-stepping, medium-stepping, and slow-stepp!ne rotors. The 

control multi-switch has 6 poeitions which control the stepping ot the 

three rotors of the keying unit as foll.owe: 

i.· Por explanation of stePPJnci of the contr0l rotors, see paragraphs 

imm.edia. tely below. 

·2. The controi multi-..switoh ca.n be located by means of notine the 

n\lmbors l,, 2, 31 41 51 6, on small square plate which contains 

switch with pointer. 
Position of 

Control Switch 

l 

2 

3 

4 

s 

6 

REF ID:A523186 

Fa.st Rotor 

l 

l 

2 

2 

' 3 

Medium Rotor 

3 

2 

1 

:; 

2 

1 

E. Kei:ing Ingtru.chi.ons 

Slow Rotor 

2 

3 

3 

l 

l 

2 

the keying instructions for using Keyine Unit M·229 wi&h Converter 

M-134; ll-134-A are as follows; 

Oonv~rt.er ~l.34; M.-134-A used in eonjunction 'Wif#h Key~ Unit I.t-229 

employs S !(.eying elements. Six of these keying elements a.re changed 

daily; t.wo are changed mt.h every message. The six dally keying elements 

are as follows: 

l. 'l'he oip,.t>ier rotor assembly of Converter M-l.34; M-lJJ+-A. - The 

rotors are seleet.ed and arranged daily a.eeording to the cui~rent 

c1pher-roto~ assembly of the ayetera. 

2. The control rotor assembly of Ke,.ing Unit M-229. - ·The rot.o1~s 

are selected and arranged <laily according to the currant controlrotor assembly table of the system~ ' 

:3· The plug a.'ld jllck arrangement on the te~.mina.l strip o:f Converte1• 

r.1-134; M-134-A. - The pll)gs and jacks are arranged. daily according to t!1e current Plug and Jaolc table of the system. l'l'he 

et'.fect o:f otu.mging the plugs and jacks is to switch the bru~d.s 

of the left, stator of the k,ying unit so that. they are connected 

to different cipb.er-rotor solenoids. See toot.note 2, page 

ru1d associated ext.1lanation_ in text.) 

4, Setting of 't.t1e control multi-&ldteh. - This switch, whieh is 

located to the le.ft of the Ke1ing Unit,, is set daily to one 

ot its six positions as indicated in ti.le eurrent control switch 

table of the system.. 

45 
5. Initial alignment o.f cipher rotc>rs of Converter 1'-l.34; M-l.)4-A. - The daily initial alignment. of the cipher rotors is found in t.he 

current table of the eystem marked "INITIAL AJ.IGNllEN'l'a, Th.is 

initial alignmait. is used during an entire d£\V but cannot be ~ 

at the beginning or tho de.y and then forgotten as can the first. 

four daily keying elements. The cipher rotors must.be aligned 

to the INITIAL ALIGNJSNT each tiltB a message is enciphered during 

t.he day. This init.ial aligru:nent ia tha.t of the oipher rotors 

used for encipherment of the internal message indicator. It. is 

never transmitli•d• For detail, see e.xplana.tion of massage keying 

element" below. -

6. Initial ali~'1lent of the control rotors of Keying Unit M-229. - The same table and group of letters is used for the daily alignment of the control rotors as is used tor the da.iJ.3 alignment. 

of the cipher rotors. It is found in the current table of the 

syste.ra marlt:ed "ImttAL ALIQN.MEN'f1.t. The coi: trol rotors must be 

aligned to t!1e first thr&e letters of thie INITIAL ALIGNMENT 

ea.ch time a message is enciphered.. this initial alignment is 

that of the control rotors W;led for eneipherment of the internal 

message indicator. It is never transmitted. For detail,, see· 

explanation ot message keTing elements below. 

The two message keying elements are as follows: 

l.. Alignment of cipller rotors to the intemal message indicator. - The internal message indicator is the initial alignment of t!le 

rot.ors when eneipherment. of the m8$saee text is begun. It is 

determined, enciphered, and used as explained below. 

2. Allgpment of the control rotors t.o t.he first t.:1ree letters ot 

the internal message indicator.,, - ·The internal PAS.sage indicator 

is detel'mined.• encip..i&red, and used as explained below. 

A group of a.ey five letters eXcept X and Z ~ selected !! rangom 

to be used as the internal message indicator. For purposes of exampl$, 

suppose that the inte'rnal message indicator selected is TLBIH. Since 

the internal message indicator is the group used as the initial. alignment. 

of the rotors when oocipherment of the message teXt is begun, it must 

n•ver be transmitted in tine elE)ar but must be disguised for transmission 

to the deciphering opera.tor by anc.iphering it •. The·interna.J. message 
REF ID:A523186 

, ' 

alignment. \Vi th the rotors ao aligned, encipher the 5-randoml.y :selected 

letters (in the example, TLBMH) by typing thom on the keyboard of the 

typewriter of the converter. The 5 ... 1ett.er cipher resultant of this en ... 

cipherment is the external message indicator. After thus determining 

the external message indicator (which is later to be transmitted with 

the message)~ align the cipher rotors to the five letters or the internal 

message indicator. lUsing the 5 letters of the internal indicator of 

the example, illgp. the cipher rotors to TLmm). 0 Then align the eon trol 

rotors to the first three letters of th~ internal message indicator 

(examples TLB). The dally keying elements having been oet at the 

beginning of the day, the converter and keying unit are now in complete 

readiness for typing the plain text of the message to produce cipher text.. 

To decipher the message,, all of the keying clements are set exactly 

t.he same wa, aa in enciphering. The onl,y differences are that. t.he encipierdeoipher ·switch is. set- W. decipher and the external message indicator is 

typed to produce the internal .message indicator.. When the inteme.l .message indicator is thus derived, the rotors a.re aJ.igned to it and the cipher 

text deoiphered. 

47 
P • Qrntogaph&c S.cgptr1 

ibe securitJ of Conv.rt.er ll-134-A with l.,-1ng Unit 11-229 is 

dependent on the following; At leatt 10 messages in depth· or flagrant 

misuse of the indicator ayet• are necessary be.tore elements of the 

machine can be reconatl'Uo-ted. The number ot exhaustive trials necessary 

to identify known rotors is very large, though not as grea.t as in the . 

case of Converter 11-134..C. The number ot trials equals 60 rotor arrangements for the cantrol maze times ~Ox 9 x 8 x 7 x 6 roto~ arrangements. 

for the cipher maze time 265 rotor alignments ti.mes 120 jack and plug 

settings time 6 settings tor the control switch. 

Alt.hough no security studies have been q9MU~1i-ed on either Converter 

M-134-A or Kqing Unit ll.229, comparisons have been ~e with Converter 

M-134....C. Even tho~ th,o pnJ~e.qt Couverte~ M-l..34-0 ha.a greater security 

than Converter M-134-A had, as it was used, the latter was the· best 

machine of its day and its chief weaknesses were the .i.ndicat.or.system, the 

tape makeup, and the operating procedures. Since t:.he machine with KoJing 

Unit M-229 incorporated many ot the features of Converter M-l,34-0, its 

security approaches that of the later machine. However, more variations 

of the cryptographic elements are possible in Converter :M-134-C, as 

indicated. below:· 

More variation in rotor speeds is_ possible in Converter K-l,34-C. 

There were onl.v 120 plug.and jack settings in Converter M-134-A 

as compared to 10~ 'Settings of the index maze 1n Converter 11.-134-C, 

1.. ThLi cryptographic security ev&iua.tion is . copied trom ''Historical 

and Oryptological Summar;y of Cryptosystems•, Volume I, (short title• 

ASAG-23). 
Al though t.he mt nimum guaranteed cycle for both ma.chines is 263, the addition of the t"° 14.._an rotors in the first and fifth pOsit.ions 

of the Converter M-l'.)4.....0 control maze provides 676 different cycles 

of 26'. 

The us• of reversible rotors :1n OonTOrter 14•134-C greatly llicreaeea 

the number or rotor a.r.rang«he.nts. 
REF ID:A523186 

CHAP'lER ,I. COIWERTER Y:-1:34-B (AND OTHER UNADOF'l'EQ 

MODIFICATIONS OF COt"VER'l'ERS M-l.34-T2 and M-134-n) 

Converter M-134-B is an adopta.tion of Converter M-13l~-T2 which 

proposes oam-w'aeel control of thQ enciphering rotors insteadcof Baud.Qt 

code tape control, C'a.1t-v1heel contraUbg of the encipberine rotors is 

covered by Patent Application lC!l,244,, .filed by William. F. Friedman 

. . on October 23,, 1936. !Jo model was built. because the introduction of 

Converter hl.-134-C (see Cl1apter XI) macie it unnecessary. l The basic 

consideration2 of the unadopted meohar1ism tor controlling the stepping 

of the rotors or Converter M-l,34-1'21 proposed by :Mr. Friedman in April 

1935 and .filed tor pa.tent. in October 1936 wa.s a series of notched wheels 

driven stepwise by meshing gears. The notches were arranged on the 

wheel collars in random fashion. The notches on ea.ch ·wheel controlled 

a contact tor opening a..'1d closing a circuit to the stepping solenoids 

of each cipher rotor. The number of 0 steps" around each notched wheel 

was different in order that the length of the cycle would be mueh longer 

that the distance around any one wheel.. The key provided by the randomly 

placed notches on the stepping wheels could be lengthened in several ways: 

(l) the number of notched wheels could be double the nwnber of cipher 

rotors {instead of equal) so t..hat it would take 2 notched wheels to 

control one e.ontaet; l 2) the notches on the wheels were to be contained 

1. Letter, ,To War ·p1a.r1s and Training Division, From Research and Development Division, Signed: W.S. Rumbough, Major, S.C., 9 July 1935. Filed 

in Folder 2, Specifieutions, CSGAS-80. 11 It is roeommended that no 

steps at.her than those already determined upon be taken at present in 

connection with the current development ot Converter M-lJ4-T2." 

2. See description and sketch, si&led William F. Friedman, dated 8 April 

1935· Folder 2, Convert.ers .M-134, M-134-A, Specifications, CSGA.S-80~ 

so 
REF ID:A523l86 

on .removable collars which could be roplaaed by collars with a different random arrange.7llent. of notciles; (J) t.he notched wheels ti-&re to be 

interchangeable. In June 19.35, Mr. Graham made several suu~eations !or 

chact;ing the mech.anico-:-eleot:ricaJ. set up of the above invention. In 

other words, the basic principle of the second arrangement i·:as still 

the use of notched wheels for closing contacts to complete t:1e circuits 

to tile rotor··stepping solenoids, but tihe exact mechanico-eleetriaal 

arrangement was different.l 

Although the Converter M-l.34-Tl was not any longer being considered 

by the A..l"'fJJJ/, an arrangement of the above type2 .for control.line the one 

rot.or of the earlier converter was also proposed by Mr. Friedman) 

. Ml:.;~~ril 1936~ Mr. Friedman .conceived another modi.t'iea.tion ()f Conv~~~·~:;~;+:3l:.-Tl, the basic principle ot which is as follows: Instead 

of employing the comparing circuit to control the starting and stopping 

.ot the commutator wheel, t..he wheel was to be kept in constant, regular 

l. See Sketc~1 11 signed \Jilliam F. Friedman and George A. Grahan, 17 June 

1935. Filed: Folder 2, ~nverters M-134, M-134..;.A, Specifications, 

CSC-AS-80. 

2. T'nat of using cam wheels instead or Ba.udot-cod.e tape. 3~ Pe.rt of ?.Jr. Fried.r.an's own description of the n.rrange.ment is as follows: 

"The eryptogra.ph consists of a single, constantly :rotating, 26-setment, 

26-cha:racter commutator wheel of the Hebern type,' controlled by a control system including a aet of rotatable, differential cam wheels. 

This control system consists of fiv~ or a multiple of five earn wheels 

w1.1ich operate make or break contact levers and their action {by "ausing 

suitable interaotion between sets of five car~ wheels in case 10, 15 •••. 

eao. wheels are.used in sets or fives) results in settin.i; up five-unit 

code,- 3.a.udot resultants. The cam i::!leels are of different diw.eters, 

individu.ally rota.table in stopidSe manner under control of the keyboard, 

the nurilbe1 ... s of positions of the various cam wheels being preferably 

prime to one another so as to yield a very long resultant enciphering 

key of Baudot permutations, there beine a. total of 32 such permut~tions.H 
RE.F ID :A523186 

rotation, and the comparing circuit was mere}¥ to dete:naine tJhen elect.ric 

potential was applied at the keyboard. Ti.1us, rlhen a. key of the keyboard 

was depressed no current reached the indicating bank through the cipher 

commutator until the comparing circuit was completed. Since the latter 

event was controlled by the cipher-key transmitter, it was obvious that 

a resUlt was indicated on the indicating bank once per revolution of the 

con:mutator, but the exact instant. when it was indicated was a .function 

of the character on the cipher-Ir..ay v;heel ... 

. • 

52 
REF ID:A523186 

Front View 

/ ,. 
,._~. - . ......... . - ~ ; 

-~:~ -:·. :.;; : -~~-; 

f,_ ,/-i ,_- - :· ·""'::' :·· .:: ___ , ' - ' 

'f l' 

REF ID:A523186 

Copz Holder MC-±§4. - The copy holder tor Converter K-134 is mounted on the base ol 

the case between the eryptogr:aph and the typewriter. Its height above the base is adjustable by upward or do~ movement on its mounting standard. A clampina pin locks th• 

holder securel,y in place. Kessagea for encipherment or decipherment are inserted under the 

sprine;-tensioned. hinge at.. the top ot the holder. A line guide moves verticaJJg·along a 

rod at the right of the copy holder. 

) 

''-
·' 

,. 

.REF ID:A523186 

Ohllnges in Keyint; InstruotJ.ons for Converter M-134, U-l:34•A 

as th.., apJ*lt" in 

"Keying Inert.ructions tor Converter 1-134• 

($hort, title: SlGP.UF), Sept 19.38 

'*Keying Inotruction1 for Converters K-134 and 

a-134-Att (lhort title: SlGJUX) 1 April 1940 

"hying lnatruotions tor converters M-l.$4, 

M-134-A" (short titles SlGLOG), March 1942 
... 

REF ID:A523186 

) 

OHARGBS Ifl mING DBTRUCTIONS FOB. co1mmm K-1.34 

-------------+----------------------- SIGPUF, Sept 1938 ....... -----------------------,.------~~~-----~------;' SIGJUX, April 1940 SIGLOG, lla.rch 1942 

Rotor 

assembq 

S Keying elements: 

2 Dail,y keying «laments-: " 

(J.) Rotor as~ - determined by table. 

(~) Key tape - determined · by table. 

3 llesaage keying elements: 

(1) Corrections between 

keytape transmitter 

and rotor stepping 

magnets. ~ 

(2} Initial. alignm«it of I 

rotors. 

(3) Initial position of key · 

ta pe. i ~ 

Each machine is provided w.tth h~ach machine is provided with Ea.ch machine .is prov.1.ded. with 

10 rotors. 5 used at a time. J 15 rotors: 5 redi-col.ored 15 rot.ors: 5 red co1ored 

Rotor assembl;v changes daily I rotors (short . title: SIGLIG) rotors and 10 gray-colored. · h 

in accordance with current ~ tor Confidential zoossages and ro. . tors heretofore used for I 

rotor assembl\r table of sys- r 10 :rotors (short title~ Confidential systems are no l 

· tem, For example,, if tllEt ~ S:IGTER). The· 5 reddish Con- longer to be used aa auch; all 

: table ehows .that for Jan l I .!ident.ial. rot.ors (SIGLIG) are 15 rotors constitute one set. · the rotor assembq is S-.3-l.- pnarked C..l to C-V; the 10 Rotor assembly changes dalla' 

9-7, it. means rotor 8 is in- f Secret rotors are marked l to ·in accordance w.ith rotor . serted 1n rotor pos .. 1, rotor ~ 10.. MEYER llflEIUlIX SECRBT · assemb.13 table of system. For. 

3 in position 2,, etc. ~MW CONFIDENTIAL ROTORS. The examp1e, the table m..'1.y show ~ 

~ rotor assembly changes dai.1¥ that for a particular da,y the ~ 

1 and is determined by table in rotor assembly is a..c.3-l-9-7 ~~ . the same manner a.s in SIGPUF which means that (gray- · 

· (see rotor assembly under colored) rotor no. 8 is in• .. 

SIGPUF). serted in rotor position l, ~ 

(red-colored) number 3 is J .. inserted in position 2;P etc • ....-~---~-·---·---~--...,...,,~""""----......... --· ~-~-~-~-~,,,.,.~L~r=-.~~~~:::\~:~,~-~-.=,- - II \\.l,jj I ... I '~~..,,.....,.,_..,.,. .. _,,.,,.,~~~=·,,_,,'-"'"'"""~·, 

(!)) l 11 \1~ 
) 

Key tape . select.ion 

Plug and 

Jack Strip 

REF ID:A523186 

.. SIGPUF, Sept 1938 

Each u ... 134 system used a different. set of'. 48 key tapes in 

duplicate., Each tape bears 

the short title or the set, 

toll.owed by an identifying 

number wtlich appears at the 

head of the tape.. It is 

these numbers which are 

used to determine the speci-

.f ic tape to be employed on 

a given day in accordance with 

! the current key tape selection 

I table of the system.. For example, the table may show th.at 

1 

for Jan l th& tape f..o be used 

· is number 17.. · 

I The correct.ions between the key 

,tape transmitter and the rotor 

1 stepping solenoids a.re estab1 llshed and varied. by means ot . the plug ~cl jack strip. These 

· . ~·. conne. otions ·.are changed with 

,· ! · -ve.I.W message as follows: .An 

, . ~~ato:r consisting of 5. letters 

is chosen at random by the operator. Suppose he selects !HBGR. 

These letters are assiened 

numbers in accordance with tl1eir 

' relative order in the normal 

alphabet thwn 

F-H-B-G-R 

2-4-1-3-5 

) 

SIGJUX, April 1940 , . . . , . ' ' . SIGl001 March l.942 

Same ...... " ' sel.e'Cllon ·is the same. 

:W:.tterence; The secret ar•tem 

has 48 tapes i'urnished in . duplicate; the con.fidenUal. 

system has JO tapes furnishE}Jd. 

in ti:-ipllcate. ' '~ ;·.~,.. " 

" 
' ! 

h 

I 

. I 

Plug and 

Jack Strip (.eont•d) 

lnitial. 

alignment 

or rotors 

Initial 

posit.ion of 

key tape 

REF ID:A523186 

lO? S~RH SIGPUF, Sept l.938 

This. th.en determines the set-up or 

the plug and jack connections but. 

these connections are in effect 

only for one mEuusage. For the next. 

1!1.essage a new indicator is selected 

at random and the order again 

der1'ffd 1n the .same "fl.'8.J! ~ 

A different initial 8liD1filent. of 

rotors is used llith every message. 

To determine the allgnm.ent_. the same 

five lettera a., was selected to derive t!1e order of the plugs in the 

jacks are used. In the examp1e 

{ft$ Plug and Jack strip above), 

the indicator selected at random 

was FH.BGB. 'llle operator therefore 

aligns the rotors by hand individuallJ 

so a• to align FBBGR on the bench 

mark from left to right. 

"'ll1e minimum length or ea.eh key 'tape i~ 

1500 characters. Ivery 10th cha.raote1 

of each key tape is numbered by a 

large number in white i.'lk. (The 1st 

.number printed by the num.berine 

ma.chin& is 010, tile second is · 020, anc 

so on until the lOOOth character,. 

which is numbered 000, the 1 being 

understood). The lOlOth character 1s 

acain numbered cn.o, ete.) To determine the initial posit.ion, the middle 

3 letters or the same 5 .lett.ers 

SIGJUX, April 1940 SIGLW, ~::.::-:.':. l.942 

Same 

· The same method. of determining the 

initial position or the key tape 

is used EXCEPf that different 

letters or the indicator a.re used, 

tor different clasai£1ca~ions of 

messages. For Secret messagesOse the lst, 2nd and Jrd letters. 

For Confidential messages - Use 

the 2nd, Jrcl, and 4th letters. 

For Restricted mea$aces - Use 

the 3rd_. 4tb, and 5th letters. 
REF ID:A523186 

) ) 

J 

SIGPUF,, Sept 1938 SIGJUX, April 1940 ' S!GWG, Marah 1942 

Irlitia.l chosen as indicator are used. T'ne 

position _of value of the middl.e 3 letters is 

key tape found by referring.to the current 

lcont 1d) table in the system. Thia table is -

called •fable For Determining Initie.l Position of Key Te.pe·n. lt is 

merely a table which assigns a 

nUlllerica1 value to each letter of 

the alphabet. For ex.a.t;lple, using 

the letters, FHBGR, and a table 

which gives the tollowing values for 

the middle 3 letters i ii • a, B • 2, ~ G = 7 .t the key tape would be set to 

position 82:7, that is, the 827th 

charai:ter of the key tape YJOul.d be 

placed at the bench mrk of t.he 

tape transmitter. 

Length or If the cryptographed text 0£_ a mes- If the crypto.graphed text. Sa.me as SIGJUX. 

message sage will exceed 20 to 60, ?:lette,r of a message will exc<ted 

SffiUJ?!p, the plain te.x~; 'will first b 100 2-letter fZOUES1 the 

be divided into two or· m.01·e approx- plain text will .first be 

imatel,y equal parts and each pa.rt divided into two or more 

\'f.i.U be treated as a separate mes- . ~pproximately equa.1 parts ~age~ and each part will be -

\ -

I treated as a separate 

message. ' 

' ~ 

l . 
REF ID:A523186 

liih m• 

Fig. I ·Converter M-134, •·ront View 

\ 

SECRET 
REF ID:A523186 

Con't'erler Mi-134 

·Pltm View 
W I I a.. I' & •!I" I ~· ·' 

S~RET 

' 

Fig. 2 - Converter M- 1.\4, Plan View 
REF ID:A523186 

Convenor fj...l_'.'A 

Rear View 
Fia .. l - Converter M-134, Rear View 

SECRET 
REF ID:A523186 

Converter L!-1)4 

Cryptograph MC-164 

Plan View 
--------------------------

..... 

4 J 

Fig. 4 - Converter M-134, Cryptograph MC-164, Plan View 

with Cover Removed 

SECRET 
REF ID:A523186 

TAB E 

Converter M-134 

CrypiOGJ'aph MC-164 

Plan Vioo 
RE'kO \tID\:tAb2 318 6 

Fig. 5 - Comerter M-134, Cryptograph MC-164, Plan View 

Showin~ Cipher Disks Removed 

SECRET 
REF ID:A523186 

Convert.or M-1'4 

Cryptograp:1 MC.-164 

(Showing Cipiler Duk Steppine Mecbtlnism) 

.. 
REF ID:A523186 

SECRET 

Fig. 6 - Converter M-134, Cryptograph MC-164, Showing 

Cipher Disk Stepping Mechanism 

SECRET 
~~~~~----------------------- REF ID:A523186 .. 

.-

;. 

Couverte;r Y·l.)li.-A ,' 

I 

/ 
REF ID:A523186 

{ir.fugtocraDn MC-164. (Reference Tabs I,. J, ,~, o.n~ ~otograpll opposite.) - The c:eyptog~aph consist.a of 

a base fra.t:lle, keyboard'; keyboard m1iversnl bar arid contract co.".1bi.naticm,, five rotors operating between 

s a.tor ole:.tents~ five l"otor s'!'.lcpping rrechauirune, rotor-stop release lever (only on llC-164-A), euoip..'iierd i11l1er reversil12 switch, tav;; tnmcitter, plu~ end jaclt strip, o1ow-releaae relay, slow-operate relay 

rd, and incident.al w.i.rint;. Interferru1ee suppi~eszoril v1ere .install®<! in order to avoid interference wJ.~ __ :1 jo.eent. l"tidio sets.. A dra:wer for storing !Iiasoo~o blanko, pencils, etc., is provided in the front of .the·· :i; 

b se. ·. · ·.~ · c-.· •;: 

: ... , 'i'ypewr•ite,1• UC-174;. (Refex-ence photograph opJ?cmito and Tabo H .mid s)., - This tqpewrit.er is a fi".OditiO .:-:: 

t ~ · 0£ the electro.raatio elect1"ieal t;vi10triter manufaatured by tfie lntomat1onal. Dusinoss Macilines COrpo -: "'·· · t. · · -~: . The m.©Uii'icnt.ion eo-nsists of tho incorporat.fon of: 26 solenoid 11i.atj1ets With dr,a.g links ru.>rat1gad to . ~- ~ 

''o J."at.c tho 26-let.ter key bars; .a univorsal lmr operatd.!:&e a con.ta.et eo.mbination upon the depression of 1 

. ~ba):'; au a.utooo.tic five-charaetor space contact tJ;ith 2 nt1le.aoid .!:11lc;ne-ts opernting upon the space bar; .:~· 

. autt)JT£1.ti.c ea+r;i.,age-return contact u.d.th solenoid magi.ot. oplim~ting up:m. the carriage-return key bar and .. ( ~.u clud:tng w. Tiarnilig ooll signal; a toJX".:•inr.,l t.itJ."'ip for into:t"cormection with tile ceyp&ograph; and capacitor 

f l" the suppression of radio mterference. The spacL1r; contact is operated by every sixth detent of the. · ulatine raek~ T'ae ca.rrlage-:-return eontuct. ic operated by a st..ud at. the ond of the tabulatina rack. 

inter.fore.nee-suppressing ~ooeitora are corm.ectod across the universal-bar Contacts and across th• 

uinala of the driving motor ~is shown in Tab $,.. ~he typewriter is pen:v.mently 'intenrlred with. the · c lotosra.pil m such a manner that the two uomullg function as .!l single unit. Tho 't.ypmrlter may be 

r.J.ted ind0t10nde:atly by striking t.ha lroyhoDSd in tile canvent:i,ozwJ. m.nner for plD,in-text recording. The 

rsiuc. owltcl'l of the eryptograph should 'be tl.w<mil to it.s DECIPHER poci.ition to cut out £ho uut.o:.0v•tie 

s cing feature .. Cow I:lo ,;st.er ,.MC-184-A.. (No~ shown) - For ~ doocription ruid pictu.re of the oopy i:1older for Converter .%· 

JI+, see Tr-:b A 1t£.ds volumo)0 The Copy Holde1· &ID-J.84-A,, for Converter ti-lJL;.~.A·is a stand.a.rd aomriercial 

w hol.cler ma'1:afactured by tho Rite-Liue Co1·"",0l"ation, 'l.'Jashint,ton, D.C. To use, it is merely necassar.r · remove i'rou. the case and set ill any convenient r1oai tion & 

etailed desorl tion continued in Tab H • ...................................................................................... ____ l. Throuzi1out .this description, ill design.a.ti.Ona of the machine as aohverter il-134-I applg equally to 

Converter &.."-134 except \vhere tho differen.ces are descx"ibed" 

) ) 
._: 

I 

I'~)· i"l'i'1 '11 ·1111" 'r.{\ h.;,''>Y·t II (• {~ 'i. I;>;; I. r I a •"ii l•u••;<; ?).(~ 1> I l~())i_;.f1 

~~~~~~~~~~~~~~~ 

. ' 

:· ·. :· .. ··. : ·: . . . . • ... .. ... .. . . 

...... . . . . • ... . 

Fig. 1-A 

.. .. :·· .··. :·· I• ii i I I . . . . ... .. ... .. . . ... . ii 

. ... ... 

I 

. . 

f,,;;' 

. . .. . . .. . . . ..... . --. . ... . . . . . .... ... . . . a ... . . •• ... .. .. SIGNAL CORPS LABORATORIES, FORT MONMOUTH, N. J. 

CONVERTER M-134-A 
REF ID:A523186 

Qo.'lverter U-lJ4 

iear View 
REF ID:A523186 

Continued tr0r:1 Tab G., 

Rotor Release Laver. Referenee pllot.c~aph optx;:~d.te, also Tats G and I. -!his lever, included only. 

on rypto~rl".!)lm 164:....A~ · io mounted on the left 0£ t.i1e rotor aooa11~]Jr f} in ·.front of tbe plQ£; and jack 

at p. By puJ.llns forvra.rd nn thin lever the rotors m .. e disengaged i'rom all pawls nn.d are free to be 

tur ecl in either direction. -

,, 

./ .. " 

Base V1~run.0:.. See also Tab G • ..;. 'E&o oose frame is a mooifica.tioo of tho uase of the Remington noiset.2r11ewritek" Model lO., llla!J:utactnroo i.>y tbe Remington iJ~iseless fypet<rlter Works, Middletown, Connect#i 

IJ.1 o1eiil.ents of the ceyptogt>ltph ore ffiOUJ!ted on ·this fra.m.o • 

. ;, 

··. ~! 

,i 

... j 

.. ·," . 

•·, 

,._- +-., . ' 

C tinued in To.b I. 

) ) 
REF 

••.:··.··.:·::·· 

:··. :· • •• t\ •• .. ... . . . ..... ... . . . . I._ 

ID:A523186 

:··· :·· ···. :·· :·· ·:· " '• • 0 •••• • : : .. ... .. . . ... . 

. . . ..... . . . .. . . ... . . ... . 

I 

... . . . ... . . . .. . . . 

"' 

, ... ... . . . . 

SIGNAL CORPS LABORATORIES, FORT MONMOUTH, N, .J. 

Fig. 2 ·A CONVERTER M-134-A 

REAR VIEW 
REF ID:A523186 

TAB X 

Convert•r »-134..J. 

Cryptograph MC-164-A 

~lo.n View, Cover }lt)moved. 
REF ID:A523186 

Kvboard. - T!:1e standard typewriter keyboard is used., but all keya 

other t.tian the 26 letters of the alphabet, the since bar and one blank 

!«ty have been eliminated. The blank k07 ia blocked up inoperative and ie 

used to provide a euide key for the normal posit.ion of the opera.tor's hands. 

A keyaoard lockingmeche.niar:'l has been provided to make it impossible to 

depress two keys a.t. th$ S&..'1.e tine or to depress a second key until tb.e 

first has been released. T'nis mechanism consists of a. series of steel 

balls wit&lin a slot'°d eo::h>, between t.he teeth of which one and only one 

key_ba:r CAY be pushed o.t a title. Each key bar is provided with a vertical 

contact extension which operates between two contact Jiaws below the bar and~ 

when· the l:ey is. depressed, serves to close a circuit iros that key contact 

to a oolenoid under ~ key bar of the typewriter. Electrically eac~ key 

cei."ltact iilas one jaw connected in oonwon to one side of the cireW.t. oent.io.ned 

W'Mi the other jaw CO:tlJ:leeted to one of the studs of the otationary !?lat$ 

ot tb.e encipher-cl"°iphor reversing mt.ch. The indiv:l.dual circuits 

pertainin.g to t.he r...J"ious keys of t.he crypt.ograp.h aro <.'t<.> .. '1;;1ected throueh 

this aw.it.eh a.'ld then through the wbole se.i of st.at.ors a."ld rotors to th~ 

aolenoi.de of the typewriter. The· ~Y <=on tact jaws or the cryptograph a.re 

ot the wipin5 type a.."ld should ei vei. a minim.u.'Il. of trou~lo,. Ii' a key tends 

to "atiek; ~ tbc.t ia, wne.n a:. key has ooen depressed ood t.rJ.on relea.God and 

faila to aprine ba.ct to inoperative positiQn, t:'1ia is probabl;r oaused by sowe 

of the ba.kelite or th,e cont.a.ct. ext.a.'1Sion wearing off and :'.'orning abrasive 

forei@'l mat.tex;> to make tt1e contact e,;t~e.n~ion: stick betwee..x1 the conta~t jaws9 ~ 

To remedy hld.s sitw.tion, all tlnt. is neeessa.ry is to place a very small 

a:oount of o good grade of petroleurn jelly ( wseline) on the contact ja:ws,, 

ueing either c:. toothpie!i. or thin ellp ot paper and t~1en uorl~ the key a 

ttlW tioea t.o opre.'ld tho lubricant in a thin .fi.lhl on the eoz1tact oo:tansion,, 

I\ez~;;oa.rd. Universal Bar ...... Ti1e keyboard 1$ equippec with a universal 

bar mounted transversely end diroctly b&.-iea.th t~1a key bars so that t.'10 

depression ct ~ !roy rota.tea .tt1is universal 00r on ite ~ds to close, by 

r:.aans of o. lever extension, the universal-bar cont.act O<L"ihi.:10.tion. 

Keyboard Universal. Bar Contact Oombi.oot;ion~ - The eoJ1t..:i.ots of this 

combination are in ltmake" relut.1onr:;h.ip tVith the universo.l 'bar in sueh a r.:iar~~er thai the depression of any key causes those contacts to eloeo befo~e 

the individual h"Oy contact. closes. It is inporta.."lt tnot t1ds rel~tionship 

oo preserwd to:r propo:r opei"a.tian of the er-ir-tog:rapll.. Upon pel"r'.J.tt.ing 

tho h--ey to rioe {return to normal) 1 the universal eontact.s o~ atter the 

individun.l key aontact opens. 'f21c p;>oition of the U."tivorsal bur contacts 

in t~1e circuit is ahe'N.ll in !ab 0 and their function is Sjtplained in detail 

in Ta.b • 

Rotors. - a. Rotors SG-Ut. lach converter is provided with a set o:r 

10 rotors w1.lich are to be used only for SECRET messages. Each or th~se 

rotors is identified by a number engraved on its inner face. The short 

title SIGTER should be written in India ink on the inner face ot each 

rotor, near the identifying numbor. The rot.ors a.re differently wir8d as 

explained below, but they are all mechanicall;y interchangeable though, or 

course, electrically and C~i'PhicaJ.11 tiwy are not identical in their 

·eLectr;;. Only 5 Of th$111 a.re uhcl at. one tLrJiG, selection being made 

Description 21 ffitbt! agp$lJ!g«t ;ln tyb !!. ., • ·< ' ' 

.. ~ ) .-~ --:'; ', 
. . . .. .. . . 

. 

.. 

.. . .. 

. . .. . ... ... . .... . . ....... 

. .. . . . .. . . fi ••• ,. 

SIGNAL CORPS LABORATORIES, FORT MONMOUTH, N. J. 

CONVERTER M-134-A, 

CRYPTOGRAPH MC-164-A, 

PLAN VIEW, COVER RE''iOVED 

I 

1 

1 

1 

1 

1 

1 

1 

1 

1 

1 

1 

1 

1 

1 

1 

1 

1 

1 

1 

1 

1 

1 

1 

1 

1 

1 
REF ID:A523186 

TAB J 

Converter Y.....134-A 1 Ory.pto graph U.,..164-A 

'Plan View 

Tape Tranefilit;ter YO-l.8.5 ood 1-> Rotors iemt1Ved 
REF ID:A523186 

Description or Rotors continued from Tab ,!. 

according to keying iiist.ructions. 'lhe ; sr}lacted rotors are inserted into ; rotor positions according to 

a key and positioned to rotate bet,ween six stators. The four intermediate stators :separate the rotors and 

a.re provided with distributor fa.oes against each rotor. T'.ne right. and left stators a.re provided with 

distributor faces int.ernall; contacting the end rotors, and are extemally connected by means of stud t. 

• s to the key contacts and the ts1:iewriter solenoids through the encipller-decipher reversing mt.ch. 

g an.Y change in the 'Wiring to either the right or le.ft stator, follow the ilistruotions in Pa.r • .31 o 

rating Inst.ructions for Converters M-JJ4 and 11-134-A" (short t.it1e: SIGKOC). Each rotor presents on 

eac face 26 segments, w'nich are in contact with 26 opring and ball. contacts on each stator. The connectio s through the intermediate stators are direct. The segments on one· !ace of each individual :rgtor are 

wi.r in random fashion to the segments on the opposite face of t.he rotor. The $Xposed periphery of~. _ rot r is divided into 26 positions designated alphabetically from A to z. No through shaft is used, ~ch- --~~ 

rot r ·bef.nt rotatable upon a sprine-tensioned ball .in the center of the stators. In order to remove ~- ' ... :-~J 

rot s 1t iS first necessary to remove the met.al lid. whieh covers the rotors when in posit.ion. This ""'- ,. r:'-~~~' 

si.10 ·~'~one quite gently by era.aping the lid at. the sides and. rockirig it uith an 'Qpward motion, be~g d~ 

car nL t<>:8et,.. the vertical extensions and protruding buttons of t.he plungers of the roto. r . stepping >~ ,, . .-:· ··--=~·~ 

o.ec -·· 8!llft.)~~e~ ~ab I) centered within the holes in the lid so tfit the lid. enn be lifted clear wit.ho~-;; -o:!! 

str g ~e buttons or the vertical . extensions of the plungers. After this has been clone 6.J\Y part.i ., :c,;~ 

rot · is '1.m.pl.y withdrawn from bet;ween the st.a tors. Each rotor presents a scalloped edge to taeil1t.ate·1 · • ., 

set · g. or.: the rotors by hand and to act as positioning cent.era in conjunction with the ·step-.tQrward 

mecj .· -~ In setting the rotors to an initial po.sit.ion t.he7 may be turned in one direction only - . ·· 

the fron~, of the cryptograph, in Cryptograph llC-164. In Cr,pt.ograph :U:C-164-A rotors may be turned in -.it; er 

t.i-on.'.by pulling forward the rot.or-release leTer. It a rotor is to be advanced ~ a few at.eps (t. _ · 

bes to< do so by depressing the button extension of the steP-forward solenoid pl.unger located directly. ; -~ 

bet each rotor position. Bμt, if a rotor is to be advanced more than a. few steps it is 'best. to depreaa 

the utt.ori by a. finger of one hand~ move the rotor forward by the fingers of the other hand until within 

two or three steps of the position desired, then release the rotor and complete its positioning by depre 1ng 

the button. As regards electrical continuity through the combination of rotors and stators, there are 26 

wires connected to each end stator and 26 circuits·· through t.he rotors no matter in mat. position the rot..ora· 

happen to stop. - Therefore 26 through circuits a.re provided at all times even thoug.>i the relationship .of 

all circuits is altered by any rotor movement. 

DescriJ2AAori of Rotors continued on Tab I. 

l. This does not appi, to Cryptograph KC-164-A; as a well has been eut in the cover to permi.t insertion 

and removal of rotors without remving cover. 

) ) ) 
::·· :·· ···. :·: :·· ·:· . . . . .. ·. :• : .. ... .. . . ... . 

. . .. . .. . .. . ..... . . . . . . . . . : I • : I •• • : ·, :· : 

··- ------:- ~....,_-· -.-~--. 

... "\> .. 

. . . . .. .. :Ii .i . . ... ... . . . .... . . . . • . l: . : .· ... SIGNAL CORPS LABORATORIES. FORT MONMOUTH, N. J. 

CONVERTER M-134-A, 

CRYPTOGRAPH MC-164-A, PLAN VIEW 

TAPE TRANSMITTER MC-185 AND 

2 ROTORS SG-14 REMOVED 
REF ID:A523186 

TAB K 

Converter 11-l~-A1 Crypt.og.raph KC-164-A 

Rotor Stepping.ilachanism 
REF ID:A523186 

Description or Rotors continued £rom Tab J. 

Rotors SG-1.5. - Ea.ch converter is also provided. with a. seeond set of 5 rotors 'tlhieh are to be used on]¥ 

£01• CONFIDEMTIAL messages. These rotors are wired differently from. Roto1~s SG-14, and their met.allic rims . are different in color from Rotors SG-14, to make them easily distinguishable. The short title SIGLIG 

.should be written in India ink on the inner face ot ea.ch rotor, near the identi.fying number. The nature and 

functio of Rotors SG-15 are the same as those of Rotors SG-l4, and no further description is necessary. 

fl . and Jack Stri • lRe!erence photograph opposite and Tab Q.} - Five plugs, cords and jacks are cont.he f :ve circuits between the tape transmitter contacts a.nd the rotor stepping solenoids. The 

connected tot.he tape transmitter contacts and are numbcred.accordinoty froml. to 5 inel.usive. 

The ja.c a.re eonneeted to the rotor solenoids s.nd are also. numbered respective]¥ from l to 5 inclusive • . When the connections at t.ilis strip M'tt dire.ct; j .e~, cords l, 2, 3, 41 5 connected to jacks l, 2, 3it 4, 5, 

;esP'!ct;.i: !z.1: then the lst rotor $teppiile solenoid. at the lert as one stands .racing tile cryptograph ia _ . .. __ .\\ 

controU . by~the transmitter pin nea.re ..st the observer.. T'ae pluz and jack connect.ions must ·be establl•ned: -··i 

At.id ch . d a¢:cording to special keying instructions, ailiee they serve to extend the cryptographic ae ·"--· ·.:: ~1 

of the if\~· . ·.. . . ··~~::·~ __ u.~, 

Ro · · in Kecllanisn. (Reference photograph opposite.) Each of the five rotors is equipped. ~": ~~J, 

nu in . ·.' steppirig mechanism comprising a solenoid, tension spring, step-forward pawl end l.oea.tion ~~~" ·~ jJ roller!. '!h~··;~dividual solenoids are controlled by the contac;ts of the tape transmitter. Yfnen a cont~t: :i· .. ,,=-I 

closes· ~ ·4rouit through a given solenoid, that solenoid draws down its plun.3er, buildine up tension jln·::.· :::~~' a spring·. »Oar the end of the stroke and step-forward' pawl is drawn into engagenent 111.th a ratch.et tooth.~ ';:;~J on ti:1e sociated rotor. Up:m de-energization of the magnet the energy stored 1n the spring ia delivered 

to adva.ri 'the rotor one J::>Osit.ion through tho step-forward pawl, which is disengaged fol.lowin13 this acUon . : :i~ 

A loco.ti i:c'ller and arm ·a.re ~ombined with the step-foftard act.ion in such a manner that a definite at~ · . position .fo~~the rotor is established. 'l:i:1e roller is positioned beneath the rot.or and falls into tne ~· ,· - "· 

scallo . edje on its periphery. 'the step-forward aolsioid. plungers are E»';:te.nded through the cover of \he 

crypto ph into buttons which can be used to step the rotors forward manually one step at a time, or to 

permit t e manual disengagement of the pawls from ·the rotors in order to faeilltate their rotation many' 

steps at. a time, as noted above. , 

Continued in Tab L. 

) ) ) 
.... :·· ···. :·· :·· ·:· :··. :· ·• . •... :· : 

•• ••• •• • • ••• • 

I'~)· i"l'i'1 '11 ·1111" 'r.{\ h.;,''>Y·t II (• {~ 'i' I;>;; I. r I a •"ii l•u••;<; ?).(~ 1> I l~())i_;.f1 

~~~~~~~~~~~~~-

-

. . . ..... . . . . .. .. .. . . . ... ... . ... . . . . . . . . . . . . ...... . . . SIGNAL CORPS LABORATORIES, FORT MONMOUTH, N. J. 

CONVERTER M-134-A, 

CRYPTOGRAPH MC-164-A, 

ROTOR STEPPING MECHANISM 

I 
REF ID:A523186 

TAB L 

Converte1~ M-1.34-A, ~it.er MC-174-A 

Showing Sp~eo arild Co.rri.age Return Oonta.at$ 
REF. ID :A523186 

Continued from Tab Jt. 

Automatic Carriage Bet.urn and Line Feed. Action. - The typewriter carriage in progression from right 

to left. operates a warning bell $igna.1 three characters priDr to automatic carriage.return in fypewriter 

MC-J.74, and five characters prior in Typewriter MC-174-A. At. the end of the line a stud at the end or 

.the tabulating rack closes the carriage-retux:n contaot which completes a circuit to energize the carrl.age-

'retum aolen-oid. '71.'.lis solenoid operates to per.form the carriage-return and lin~.reed funct.ioris sim.ul.t.aneo • This £unction is, of course, automaticaU, pert'ormed regardl.ess of the position ot the enc:iphel'- deci er switch. 

utomatic S cin Action. - Bvery sixth detent of the typewriter ta~ulat;4.ng rack closes the spacing 

cont.a t which is mounted on the rear of the typewriter. With the rewr$e nit.ch in ENCIPHER position, 

a c; W.t. is then comp1eted t.hrour)l tne type.writer space-pole, sin~tilt*aw switch 11bich .forms one elem 

ot .,th . gann reversing switch, to the tabulating-rack epacing cont.act Snd back to power.. .The· spaee bar "·~, ~- -i:-; 

of'.. · . typewriter is thus operated at every sixth detent of the tabulating rack, and the characters in .,. __ · · _ -'.j 

cryp .: · at\\ are printed in groups of five~ With the reversing switch in DECIPHBR position the eireuit. 14.' - - ~ ~~ 

op(,n - OJ" the ~1.ngl.e-pol.e, single-throw switch$ so tha.t closing or the· sr,acing cont.ant on tbe crYJlt.ogral.h ~- · _ _:,,~ 

do~. t. energize. the space-bar solenoid. · · · · . '--; -; . ;.~ 

~' - . ..:; . ); __ )j v_ ., • 

... ' 

Con inu.ed in Tab U. 

) ) ) 
• 

. . ... .. . ....... . . " . . . . . . :· . :· · .. :·. :• 

Fi:J 6 ·A 

. . .. . .. . • ·;W .i . . ... 

., 

... . . . .. . . ... . .. : : c •• , . . . SIGNAL CORPS LABORATORIES F'ORT MONMOUTH. N. J. 

CONVERTER M-134-A, 

TYPEWRITER MC-174-A, 

SHOWING SPACE AND CARRIAGE 

RETURN CONTACTS 
REF ID:A523186 

- -- -------~--------- ----~--- --
REF ID:A523186 

Continued from Tab L. 

Bectifier RA-2,3 .. - (Reference· photograph opposite and Tab N .. ) For installations mere conmercial a.c. 

is the onJ\Y power available,. Rec:tifler RA-23 is used as a source 0£ d.e .. for operating the converter. 1.bis 

rectifier has a rating of 500 watt.a at ll5 volts d.c. and operates on 60-cyele a.c. The input transformer 

is provided with taps for operation on llO, ll5 Ol" 120 volts a.-c supply. The rectifying element. consiats ot 

a t;rpe C vacuum tube, manufactured by Electrons, Inc., 127 Sussex Avenue, Newark,, N.J. To put the 

rectifier in service re.move the screws on the right-hand edge of the cover and open the h~ed section. 

Kea.sure t e voltage of the a.-c supply, th~n de.~eimine that the input trans !orrr.er is connected at the proper 

tap •. Ins rt the va.cqum tube in the soaicet and replace the cover. Make certain that the rectifier switch is 

in the " F" position before plugging the cord into an a.-c outlet. Operate t-Jte switch to posit.ion n1u and 

all.ow it o ranain in that position £or at least t.hirty seconds before advancing it to position °2. 11 This 

1'ill ·tJ'le filament of the vacuum tube to heat before vol.tage is applied to the plate. Some of the , ~- . . - .. . reetit•er ~equipped with a two-position switch and a time-d.el3¥ relay.. After the sw1tch has been ~'~- --.::;i; 

· l\dvan~ " ··.-P<>sition "211 the conTerter power cord ma::r be p1ugged into the reatJ.£ier out.let receptacle anl-c ., h::: , ~: 

the e ___ . , operated in the manner described in Sect.ion II, "Operating .Instruct.ions f~ Cal-verters 11-l~::o r~c:--~1 

and M•.134: A..•:-<(short title; SIGKOC). Ti1e rectifier shoul.d no.rmally :naquire no further attention no· adj~'::-=<~~ 

ment. ·. · . tHt event that the rectifier output fails, examine the 10-ampere fuses which are provided in e(c_!i '"''"'~' 

side ot. ·. · ',ithe input. and output circuit for protection agai.11st overloads or short-Cirelli.ts. If a tuse;~--o-y- :~ 

has n<i~ · h · ·-. ~ check the vacuum tube to make eertaih that it is making t,ood contact in_ its socket... 1£ t~f.t:~ · ~c~".~· 

tube app ts 'to be defective it. should be replaced with one which is .knO"-:m. to be operative. The reotifi~? \;:;J 

switoh sh uld a:Lways be thrown to the "OFF" position when power output is no longer desired. A wiring 

· diagram o tine rectifier is attached. to the inside of the cover .. • - J 

Gontin d in Tab N. 

) 

·., 

1,1_ 1 .-

~r.'.; 

-·--::_:) 

) 
REF 

:··.:··.··.:·: ...... . . . . . . . . . . .. . .. . . . .... 

Fig. 7-A 

...... : . . . ,. .... . .. .. . .... ··: ... :·· . . . . .. . . . . ....... . SIGNAL CORPS LABORATORIES, FORT MONMOUTH, N. J. 

RECTIFIER RA-23 
REF ID:A523186 

Rect.ifuu.• BA-2.3 

Cover Opened 
REF ID:A523186 

Continued trgm f'q~FM(;~:'. ': : 

I I c, i I;, : ··- 'f "' .. I 

J (.~1JN 'J.~~}. ; ;,:.;I 

For description of Reetifie~ RA.•23 (p1otured oppo3itie 

trlth eovcr opened.) see Tab M. . · 

I ,' 

·-·/ '-
-· 

~ .. ·. ... . .. : .. . .. ... . . . . . :· .. . • •• .. .. ... .. . • . ... 

i:..::.,. 8-A j ~ :J• -

. .. 

• I 

. 

REF ID:A523186 

. . . ··:: ·: . .... . . . .. . 

... . .. .. : : :. . .... ...... . . . SIGNAL CORPS LABORATORIES, 

' ' 

FORT MONMOUTH, N. J. 

RECTIFIER RA-23, 

covrn OPENED 
REF ID:A523186 

TAB 0 

Comrertor tl-134•.A 

Sohenatic Die.grlltl 
REF,ID:A523186 

"'', - - ,..--, .e"'-11G"t, 11~·:1 ·--~. ~ "11· -":\ !p(·''' ! ' ' 1

1 

ConSinued Im fab R • ;,\ JJ1k,;,:.' ~"·; ,~'. 

~-~·.· ,-: .. ' . 

., 

Plgg and Jack StriR• (Retmmce Tab j tor desoripUon.) 

, Sl~ Releast Relaz •. Ca.terence photograph opposit;e and Tab R.) 

The functi~ ot hi• relay is to hold the rotor steppine solenoids 

energizod tor a outt'icie.nt length ot time to insure complete plunger travel 

and aubeequent.ly to clear the circuit to the normal or open et.ate. Thia 

relq ~s a reaiatance ot 1.300 ohms and is equipped with a copper slug for $low-release action. The contacts are an application of the Burges$ 

1nolosed-type micro-mt.ah. This switch ha$ proved very depend.able in 

service and should require no attention .. 

- Slow ersrate Rel.a..y. (Reference photograph opposite and fab R.) 

This relays found onl.3 on Cr.vptograph 10-164-A. Its ehief function 

is to insure that the magnet of .the tape transmitter is energized for a 

sufficient. length. of time to advance the ke7 tape to the nw-..'t position. If the ope:rat!ng time of this relq is too short, faulty operation ot 

the <;rypt;.ograph. will reault; if too long, the speed at wh.i.Qh the cr,ptouaph may be operated will \)e reduced. The relay is equipped with a. mi~ro-adjustment. to permit eloae regulation of the time d.iay. 

Continued in Tab P. 

' ' ' ~ 

' - l (" ' 

• • 4 ~ , ' •, • 
C/IKK//16£ 

/il'ETVK# 

fOt.£#0/P 

.J'7ACE 

JOLENOIP 

,,,.,A,,,._,, ro OTHEK "•ir'Ex~Al SOl.ENOtP~ 8/#K 

C/lll'K t/16£ 

llErVKl'I 

CO/llTMT "l ~ KllCI( TIUIVL /ITl/116 . 

SP/ICING 

CONT/ICT 

MOTOR 

. . . . . .. . .. . . . . . . . • & I e I a. . . . . ... . . . . . . . . . 

TYl'EWl(/TEK 

... . 

co 

. . .. ... . 

. . 

:t ~;R' , UC . U: X A »# ) SC . CH 

'--+--+--+------4----+---+-- t - -------. ---1-'~ 

.--+---+---+--- _______ ..... _ ..... _ .... _ _._ __ - ------ ----r:-----.r-~V.-'6_J_"_JAC._"K_J_ - -n 

,!st~ .111' 'J.vc , le ,)x ,)"' , .SM ,)sc .~elf 

~'+----~ 

"'"r-Ytr51 : I 

SUJW 

OPE~AT£ 

//NIV£1r.11iL 

8111? 

' ] l 

I 

i-~ ~-} IL:====================:::tttt:t:::=J 

i I~ ~~~~=+=t=================::J I 

~=~=n~=~itN._r.=_"=~_P.:~'&=:.-~=r~::re.~~:::l=_=_=_==::::=:=:=:~::=:·~~=c.=_: "K:Y.~'P.~:=,._:=M_:~:~: ~=:it_:...,,,, __ w~~--~1-f'W-·-·~f_"-"'q~r~_,-:::~':_~ __ y--L- ______ J 

C TAPE TK"NS.H/Tn!"K · TEA'M/KA~.S r \ 

A CKYPTll6KAPlf TF~IHl/l/lfl.S I I 

0 TYP£WA'IT£A' TEli'.+f/NAl.J 

Fig. 9-A. 

Converter M-134-A, Schemati(' 1iagram 

. . .. . .. . .. . . . . . . . . •I '' e • • •• • • • E) • • 0 

•• eeo o e • • ••• 

••• . . 

/IS Vt?iT DC. 
REF ID:A523186 

TAB P 

Converter M.-l~....A 

Encipher-Decipher Re'.Versing Switch 
REF ID:A523186 

Continued from Tab o. :.i~ _;...• 1\L :\ :.•.·'~ 1 

,, -:,· '. ·. • 

1

• 

Enciftr-Deicipher ·~~ .~i.~·~ , (Ret~nce photcgra. Pi opposit.e.) !.• . s switch ia . · _· :! beAeattF the kqboard. ot the cryptograph -and 

is operated by a lever at. the front. This switch acts primarily' as a 

combination ot 26 double-pole, doul>l .... throw ftitchea in the 26 circuits 

trom the key contact jaws through the rotor and ·stator . assembly to the 

typewr1t.r solenoids. It.a function ia t.1t0-folch (l) to disconnect the 

automatic apaoing feature ot the typewriter1 (2) to reverse the connections from the left and right stators with respect to the keyboard contacte of the cryptograph and solenoids of the typewrite:r so as to produce the enciphering-deciphering recipro.cal relationship to'I:' which the conVEtrter 

is designed.. The ti.rat teat,ure has alread,r been discussed in Tab • · 

h• A.a an example ot t.l).e second feature, and a.a shoe in the photograph 

opposite, wit.h the switch in the EHCIP$R position, operation ot the ttAtt key 

results 1n the printing of a "G•" With the rot.ors in the same position 

and the switch in the DECIPHER posit.ion, striking the "G,. key results in 

the Pr.~t,SF,g or an "A•" In addition, tne reversing switch coo.t.ains extra <;Q~~~~~ -.iich function .in encipherme.nt to print. the cipher text 3=n regular 

groups ot five characters, and 'in decipherment t.o print. ~he plain text in. 

the original worl lengths. Those extra cont.acts function as two eineJ.e-pole, 

!tingle-throw switches M.d·ono.single•pole, clouble-throw switch. One single- pole, single ... throw switch connects the space-bar contact.of the eryptograph 

in parallel with the "X" key contact when tn• mt.ch is in ENCIPHER position 

and breaks this connection when in DECIPHER position. The other single-pole, ~ 

single-threw switch connec\1 the typewriter apaoa-ba.r solenoids to the 

t.a.bulating-rack spacing contact wh$l'l. in ENCIPHER position and opens this 

circuit. when in DECIPHER position. The single-pole, double-throw switch 

connects the "l" stud of the reversing switch to th• typariter ".11' solenoid 

when 1n ENCIPHER position and to the typewriter space-bar solenoids when in 

DECIPHER position. Thus, in enciphering a. message, the space bar of the 

crn>togra.ph is operated llhenever a. space occurs in t.h• plain text., as in conv«nti~ typewriter Op$ration, producing the same resultant in the 

cryptogram. as 110uld have been produced if the •xn key had been operated.. 

In deciphering the message a space "'!ll occur wherever a apace or an "X" 

occurred. .in the orit;inal plain text. T'ne let.ten in th& deciphered. 

message will therefore be automatically grouped in the original word 

·lengths. However, since in some cases what would appear to be a word · space should really be the let\er "I., .. in order to avoid possibility of 

conSuei<m or a.mbieuit1; the double 1etter "QQ" 1s used to replace the 

letter nxn whenever •xn appears in the plain text ot a message to be 

enciphered.. ajmUa.rl,y, on decipherment, whenever the eombina.t.ion t1QQR 

~pears in the deciphered text it is understood. that the plain-text. letter 

•xn ie intended, and in retyping the message the ••QQ" will be replaced by ".X•" Thus) SIQQlllN will be the 1'0rd SIX'JSEN. 

Cont.inn1d011 jp Tab Q• ·~,--;~:;, ,,-:· :, >•: •. ·• :--; .. o;-· -~. 

I. When the sWltch II in iiei-it;;e;iuii iai &;&ea bar es Eae eryptograph 

ia dead. Depressing the's~()t_'b,ar Will cona,quent.q nave no effect at all. 1- '_/' '.,_'~~'.! ·-~~,' ~, ... '.: 
REF ID:A523186 

.. ···. :·· .··. :·· . :·· ·:· . . . . . . . . . . . . .. .. . . . .. . KEYS 

G 

A 

SWITCH LEF'T STATOR 

ENCIPHER 

DECIPHER 

G A 

.... .... 

... .... ROTORS , __ 

.I' 

A G 

RIGHT STATOR 

TYPEWRITER 

KEY SOLENOIDS 

A.....___. 

G 

Fig. 10-A 

I 

Converter M-134-A, Reversing Switch, 

Schematic Diaf:ram 

•• • •• • •• • •• • ••••• • • • • • • • • :··. :· · ..•.. :• . .. ... . . . . ... . 

J 
REF ID:A523186 

Oonvertor M-l,34•4 

tape Tr~tter ll0-l.8S 
REF ID:A523186 

Continued from Tab P • 

.2· When the mtcl): ii, tit ~t.:1¥ mic.twat between the encipher and 

decipher positions the int~ .cm~•Ph ke7boJJ.r4 is "dead" but the type-

"'.'rriter keyboard is "Uv•. •· ···Thi! may· be useful at times when it is desired 

~Q operate the keyboard or the typewriter without. danger of actuating the · the cryptograph keyboard ina.dvertentJ..y. 

Tape Transmitter UG-lS5. (Raterence photograph opposite) · A• fhis unit is a. modification of the Tel•type Mod&l. Z4 tape tr&n8mitter, 

manufactured by the Tel•type CorPQration, Chicago, Illinois, and used 

C9llll'.llerciall.T in printing telegrapb,y. This· tranemitter aperates on th9 

basis ot the Baude>t o:r five-unit. code perforated in a paper tape and is 

conatrμoted. to establish five contact canbinations 1n marking or spacing positions dependent upon the arrangement of code perforations in groups 

transversely disposed <m the tape·. T'nere are 32 different permutations 

1n the .five-unit oode, °'"· sbqwn in Tab 'l' ( llhich i~ provided merol.l to 

facilitate the preparation of sp•ci.al. testing tapes when necessary). · 'fhe tape is-provided also with a. continuous series of perforations in 

line longitudinal}3, their spao1ne being identical with the sya.cing between code permutations, to permit progressing the tape conseeutively frCfll one code pe~utation to the n8Jtt.· The ta~ transmitter ~s equipped 

-1.th a tape groove and guide; a hinged retaining plate or latched die, 

often retened to merely as the nia.tch, t1 to pemit inserting the tape at. 

any desired permutation; a !•d wheel which engages the teed boles ot 

the 'tape; tive tap& pins conjunctive with the code perforations in the 

tape -and operative upon five contact l'9vers in marldne-spacing positions, 

and a magnet acting to dep~a all t'ive tape pins ~m engagement with the 

ta.pa and to step the tape to~rd to·the·nut code pe1!$1tation by ratchet 

movement of the teed wheel, after whieh the tape pins are released to 

assume their tape"-Controlled positions. When a tape pin is held down by the 

tapeJ t.hat is, when there is no hole through which the tape pin can rise, 

the associated contact lever is held against the spacing bus. Mien a tape 

pin is permitted to rise through a hole in the tape, the contact lever is 

moved over to the marking bus. 

b. The fwietion of t.he tape transmitter in the cryptogra:.i;:h is to 

step forward the rotors in accordance with the code permutations in the 

key tape~ laoq code permutation in the key tape establishes, through 

the tape pins and contact .levers ot the tape transmitter, circuits 

which energize the solenoids of the selected rotors, cau!ling the latter 

to be ll<tVa.nced one step and leaving th& nonselected rot.ors in position. 

Each tranamitter contact is connected in series with one ot ·the stepping solenoid$ thl'ough a plug and jack and the contacts of the slow-· 

release relay. T'ae selected rotor oolenoida a.re therefore energized only 

during tile intenal between the deenergizat.ion or the t.ransmit t.er magnet and. the opening of the slow-release relay contact.s; i.e, 1 between t.he 

release ot a key of the cryptog:raph and the release ot the slow-release 

relay. Hence. it. is important. t.ha.t. the time-delay setting of the slow- · re~se relay be sufficient for the purpose. 

Continued in Tab R. -: '."' . :1 t:;:,::: ,·~·~. ,~.:~~ •. : , ~, , _ . : ; f' ' .~ ~~· : 1 ••· ·; : ' ~. '<I.. -'i~' ' 

~ i : 

• f ~ I ; f / 

I ''·· 
REF ID:A523186 

• ". ' • t 

' .. : ... .,. . 

.. ' ............. _,., . •.· ..... ' ,, · .. 

• • • ' ' ' • • • ' , •. ,. • . ... • .._ r • I • • , . ' _.,, .. • ' .. _ • '• '" ~ ' , 

TAB I 

Octaverter-¥-l.34-A 

.· . Or,rpWgapb: llQ-~...;,& 

· WitinS Diagram 
REF ID:A523186 

-:.~:-~;·.;-,"°; 6~:-.-:--: i!::::-:.: . . -~ /~;1~ .,4-... --.~ ~· • .; "i;' . 

"'' ,,,.., I .' j I·,•: " !• , , ' . ! , '· ' ' , , . t ' ,j•. 1 , , ~ • 

, ~ate Tranp.tter uo-ia, cpt\aata1fl.95 fab g .. -· >I .1f'q ,'.;/'· • • + 

11• Key tapes for use with the ~iograih a re iaaued by hidier , headquarters in a coordinat-ed system of distribution described in 

epecial instructions• T'ne k'ar tapes must be handled eare.tuU.v so as 

to prevent their damage, los1, or oompro.mise. Tapes wUl be replaced br the issuing authorit.y tram time t.o time as conditions ot usage warrant. 

Detailed. directions fot their use in enciphern.!mt or decipherment are 

issued in the 11pec1al ir11tructions referred to abov.e. 

s!· The key tape ia to be inserted in the tape transmit.tor wj.tb the 

teed wheel 0£ the transmitter eneaging the teed.boles of the tape, and 

with the numbe.· red side of the tape up. Kake ce~ thai the initial 

sett of the ta at e bench mark on the ta d'e s correct . .!• the le. a e 0£ the tape transmitterJ i.e .. , the side adjacent 

to th• box containing the fuse, and set flush in the eide of the transmitter, wiU be .1bund a button. This can be pushed inside the transmitter 

to.-aause the tape to stev forward by mechanical action on the stepping 

nmehanism. 'l'his butt.on will be found ueetul 111 setting the tape to a 

specific position. 

General Desori on ot Cr to .a o Circuit • .1~ cipg.erment, - When, - or ·exam. 1 the A" key of the oryptograpb is depream, a circuit is established froat. power through the •A• key contacts, thence through the "Au reversing switch to the "A0 stud on the left 

stator, thence through the rotors and int•rI!W<tiai~ stators and out at a 

certain stud on the right stator. Assume this to be the 11G11 stud in the 

present instance. The circuit ts theu ... c~tirlued \Q the "G" · reveraing switch and through that switch to the "G" sol~oid of the typewritor ancl 

returned to power, with the result that f1G1t 11 print.ad by the typewrit•r, 11· Decipherment. - Vlhen the "0" key of the cryptograph is depressed, 

a circuit is established from po118r through the "G" ktty contact.a, t.hrclugh 

the rotors (which are, of course, in the same alignment as they were when 

the letter •A• was enciphered) and intermedia.t. stators and out. at th• "A11 

stud on the le!t stator. The circuit is then oontinU$d to the "A1t reversing switch and through that switch to the "A'• solenoid of the typewriter 

and returned to pOWer, with the result that n4u is printed by the ta'pewrite:r. 

Detailed Deaoript.ion of the Complete Circuit. 

l• · liic1pherment. Mien, tor example, the ff41t key of the eryptograph 

is cl4fpt'*S.sed, a airetiit is establlsh•d from power through the ttAtt key 

contacts~ thenoe through the "A" reveraing switch to the "A• stud. on 

the left stator. In tht.l Oryptograph MC-164-4 this circuit includes the · contact.a of the al01Mlperate relay. Assume that the path through tho 

rotor assembly' fin.all¥ ends on the right stator at the "X" stud, connect ... inB to t.he "X" reveiosing switch,. The circuit is t.hen continued through 

the sp'1cial. switch pert.ai.ning to the "X" key (which mdtch is described 

in detail la.tor and is not. a feature pertinent to the other keys) to the 

Continued in Tab s. ~-~F ~~:·' r;,:ii ~·I.' 

' ' j .• . ·. •' ·- , 
· REF ID :A523186 

D•tail!d Ptsoa»W,oa 9£ ,ll&, ~·~1 ~tr 9antJ.n91$ 1'£~ '-'t~ I· . 

•xn solenoid of the •1-cttrical t~iter :f.nd tJ1enoe. retumecl ~ ~ .. throtJ8h tn• upper o:ontta.ct. . 9! ·th• oqptogr.apb ~•areal.~ contact.' cc;n.. ·. bination. This oqmbina~ion ie opera~ad. upon the depre•ion or &l\Y key of 

the cryptosraph~ ln tha caae of t~1e Cr,ypto&l"~ph Jta-164-4 uhi• oaouit · does not; inolwi• the univer•l con.ttt-~t combi.n&t.ion. Wh.e11 t.he t,pevit.r . printe "X". the typewriter univeraal bar OJ>tr&t.•• to close its oontaot•,· completing a-c1rcli1t tbrouan the lowr o0ntact. ot t.tw oryptosrapb liμliv.r.U· 

bar combination to energize aimul.tane.ou1l3 the aio..relea.ae rel.\Y and th• 

tape tranamltter magnet. In t-he ~J:7ptograpb llQ•l6JrA this circuit, .1nclud•a 

the cont.a.of;,,; ot th• el.ow-operate reJ.a.y. Tn• tape \ranamit.ter now •ithdrawa 

ita tiV. pins below th• surface ot the tape euide_and.advano••_the ta.pt t.o 

the next ptrmuta.tion. Upon release ot tb& ttA• key of the Cryptogra.ph M~ 

{or when in CryptographMC-164-A• tne slow-operat.e relay contacts open) the 

typewriter •x• solenoid 1a d.,..nergized., its univental-bar contact opens, 

the universal-bar contact combination of the ctyptoera?l opens, and the tape · transmitter magnet ia de""9nergh.ed~ 'f'ne slow-release rela,y, however, ia 

cleaign.ed to hold its contaet cl.Deed tor a brief interval alter its coll 

is de-energized. When the tape transmitter .magnet releases, it operates the transmitter contact tongues to marking or spacing position, according 

to t.~1e code permutations 1n the key tape. Circuits are established from 

power at SR through those contacts 111hich have been operated to the .marking 

position to enegize the associated rotor-stepping solenoids. Each 

energized solenoid pulls down its plunger to tension a spring, and engages 

its stepping pawl in a. tooth of t}1e rotor ratchet. V'foen the slov1-

releaae relay conte.c t opens, the solenoids are de-energized anci the. 

associated rotors are advaneed to th$ next position by spring act.ion. 

Th& oryptograph is now · reada' tor tbe next operation of the keyboard. k· ·DeciJ?herJ!!nt .... In the preceding paragraph it was assumed 

that atrild.ng th8fflu key· or the or:yptograpb ~sulted 1n the printing 

of an. uxn by the typewritei-. 4ss\11\8 now that the key tape setting and 

all rotor aottings are unchange41 that.the rf)Versine switch bu been 

moved to DECIPHER position and that. the »x• ke,y of the erypto~aph is 

depressed. A circuit is then established from power through the "I" 

key contacts, thence through the "X" reversing mtch to the "l" stud 

on the right stator and through the rotors and intermedia.t.e stators 

to the "A" stud on the left stator. In the Cryptograph JIC-l64-.A1 th.is 

circuit includes the contacts of th.e slow-operate relay. The circuit 

is then continued through the •.A. 11 reversing switch to the "A• solenoi.4 

of the typewriter, and back to power at SR thro~ the upper contact of 

the cryptograph universal-bar cont.act ~anbination. In the ease of 

Cryptograph KO-J.64-A, this cir'cuit does not include the universal contact canbination. The typewnte:r ptinte "A" and its universaJ. .... bar contact 

closes t.o complete a circuit t..ilroUgh the lower contact. 0£ the· crypto '.."1"a'¢1. 

uni V91'$al-bar contact combination to energiz• the slow-reJAase rele.3· 

and the tape transmitter magnet simu.:.taneously. In Crn>togaph KC-164-A, 

Oontinued on,tollOJigs J?B:6G· 
REF ID:A523186 

• ' . { ~ * . • I 

.i 'f t • 

Detail.ed DeacFiptd.oa ot. U.·. Cgimlet.e -e.bcu.tt-4Cat1m.4 t'~ fab R~-

this circuit includes the con~cta Of th.e alQtM>ptra.t• rel.a,. 'lhe tape 

transmitter then withdran it• tiw pinlt and. adTancea. the b,y tape. 

Upon rel._ ot the •:P Ker of the oeyptograt:b (or 1n CrJ'pt.ograph 

M0-164....l when· th• slo..operate relay contacts open),· the "Att sol4noid 

of the·t:r~er is de1tle.rgized1 the t1pt'Wrlter tll'Jfv~eal .. bar contact 

optne a.'14 ),he eryptognl>b ·Wiivtreal--bar ·contact ·combination ~-• . · 'r.1•· t.e.pe.~tnnamitter .. magnet then rel•a.aes and. ·cqmpl.t•• circuit$' to 

the •ame roto~teppirtg ll()lmoids which 'tnitre energUed in the prooess.ot 

enciphermen.t.. 'Mlen th• con\&1tts oi the alOW"lorelease rel.q open~ the . seleoW rotor• ~·adyanced on.· st.p. The manner 1n which the circuits 

are oom})leted and the sequence of opilration are the same aa in encipher-· ment. · 

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: I ClC'i:::lB----1 

,_, 

REF ID:A523186 

,, 

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.... :·· .... : ·: 

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fig. 12-A 

Converter M-134-A 

Cryptograph MC-164-A, 

Wiring Diagram 

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• • • • • • • •• ... •• • • ••• • 

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See description ·Of typewr1.ter ».c-174-A, Tab G. 

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REF ID:A523186 

TABS 

Converter M-134-A, frpewnter l!0-174-4, 

Wiring Diagram 
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CONO 

l/NIVEli'.111L 

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Fig. lJ-A 

Converter M-134-A, Typewriter MC~l74-A, 

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•••• ••• • •• • • •• •• • • • • • • •• ••• •• 

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REF ID :A5231.86 

TAB '1' 

shown in place on 

Crn>toarap\1 llC-164-A of Convert.er M-134-4 
--------

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REF ID:A523186 

TAB U 

K07ing Unit ll-229 

(Short. title: SIOOOO) 

(Plan View) . 
REF ID:A523186 
REF ID:A523186 

Keying Unit M-229 

(Lett fJtator View) 
-1 ' ' . .. '' .. ,,. ' ~- •· 
REF ID:AS23186 

TAB W 

Ke71ng Unit 11-229 

{Short title: SIGGOO) 

(Rear View) 
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Ke3ing Unit y ... 229 

{Shor\ title~ SIGGOO) 

(Cover in Pl.ace) 

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TAB Z 

Wiring~ 

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WIRING DIAGRAM 

KEYING UNIT M-229 

SECRET 

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LEFT, STATOR WIRING 

A. 7-8-9-10-11 

B. 13-14-15-16 

C. 2-3-4-5 

D. 18-19-20-21-22 

E. 23-24-25-26 

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MICRO • ~•?o .SWITCH I -

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REF ID~ A523.i:--8-6--

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TAB AA 

aignal Corps Technical Committee 

Meeting No. 146 

Supplemental w.nutes 
SIGNAL OOBPS TECHNICAL COMMITTEE 

MEETING NO. 146 

SUPPLEMENTAL MilIDTES 

1. In addition to the matters acted on and reported in Minutes 

of Signal Corps Technical Committee Meeting No. 146, January 11, 1937, 

the Committee took the following actions with respect to Converter 

type M-134: 

!!:• Military Characteristics: 

(1) The Committee recommended that the following military 

characteristics be adopted for Converter type M-134: 

(a) This machine should be designed for the fundamental purpose 

of enciphering and deciphering messages with speed, accuracy, 

and the highest degree of cryptographic security. Secondary 

to these characteristics, there should be a minimum number of 

switches, keyi.ng elements, etc., which must be set before 

proper operation can begin. 

(b) The cryptographic operations should be controlled by an external element which is variable and is not a.n intrinsie part of 

the mechanism itself, such a.s a perforated tape similar to 

that employed in printing telegraph apparatus. The underlying 

cryptographic principle should be that of a continuous, nonrepeating, unintelligible or random-mixed key sequence of 

characters governing the encipherment of successive letters. 

(c) The machine should consist of two unite. (1) a cryptographic 

unit hereinafter called the 1 cryptograph", provided with a 

stand.a.rd typewriter keyboard, and (2) a recording unit suitable for making a printed record o~ the work done by the 

machine, preferably an electrically operated typewriter, hereinafter called the "typewriter". The cry:ptogra.ph is the part 

of the mechanism in which the encipheriDg and deciphering 

operations occur; the typewriter is electrically associated 

with the cryptograph and is to print the cipher text, in c~se 

of encipherment, in 5-letter groups, 10 groups per line; in 

the case of decipherment, the typewriter is to print the plain 

text, preferably in their original word lengths with proper 

spacing between words. · 

(d) The minimum speed of operation should be 30 words per minute. 

(e) The cryptograph and the typewriter should be mounted upon the 

same base with fixed electrical connection between the two 

units. A side-by-side arrangement of these two units is preferable to a tandem arrangement, so that the keyboard of the 

\. ,, 

............ ~· ~. -· '-...... . 
<'-) 

• 

C17Ptograph as well as the kqboard of the typewriter are both 

immediately in front of the opera.tor. 

(f) The apparatus should be designed to operate on 110-volt, D.C "' •• 

power source. 

(g) The weight of the cryptograph including its carr,1ng case should 

not exceed 50 pounds; that of the typewriter including its 

carrying case 60 pounds. :Both units should be rugged in construction and capable of withstanding jarring incident to transportation. 

(h) The entire assembly should be so col'Jlltro.cted that in ease the 

typewriter is out of commission for aey reason, cryptographic 

operations may be continued b~ means of electric light-bulb 

indicators on a lamp board on the cryptograph. 

(i) There must be incorporated features to suppress interference with 

radio receivers operated in the vicinity of the machine. 

]!. Standardization of Equipment: 

(1) Acting upon the recommendation of the Chief Signa Officer, 

the Committee recommended the adoption as to type and classification as 

Stand.a.rd of Converter type M-134. 

C. L. Marriott, 

Major, Chemical Warfare Service. 

lvt~~_/ C. R. Huebner, 

Major, Infantry. 

~ Major, Cavalry. 

H.B. Holmes, Jr., 

Major, Coast Artillery. 

~c-2, . (_/"(~~~e..-~ A. W. Marriner, 

for 

Haskell Allison, 

Major, Signal Corps. 

W. S. Rumbough, 

Major, Signal Corps. 

11 cal CvU/<b /}J/.li Mr. Nathaniel White, 

for 

D. M. Crawford, 

Lieut.Colonel.Signal Corps. 

/~ ,/~~-/-~~-~ /~- - • • Browning, C7' 

Major, Signal Corps. 

Acting Cbairma.n and Recorder. 

Major, Air Corps. r::::::" r·::-.1 .·--- r .--. : - :., • 

-2-
}•' ·v· 

CONCURRING: 

·/,(/. - - . 1Y</' .. I '..: ' ' J 

J touis E. Hibbs, 

Major, Field Artiller,y. 

~· /.~~~ ....C-tJ. P. :Bush, 

Major,Signa.l Corps. 

A. D. Ropp , Capt., Quarterma_.t.r CofPs· 

cl 

APPROVED JANUARY~' 1937: 

: . ' : -· . ~ 

~-.;~ /~ ,'I( /, // 

,l _...,.../ ''.J/ ' / / / 

~. i 'i'-_,,/ ::~: ' \J 

J. B. Allison, 

Major General, 

Chief Signal Officer of the Army. 

-z- I 

r