, • REF ID:A10502 • 

This ~invention relates to the addition of certal'1.F&JiJ.J.~ and methods 

to printing telegraph systems for the purpose of enciphering t.he message. 

1925 M.·~v .._ This invention relates to the addition of ce:i!e~i~~~e5a~ methods 

to printing telegraph systems for the purpose of aut;onaticallj ene.lphering 

and deciphering the message. 

0U/£r: r OFFJCE 

one object of this invention is to proviae re~t1'1{ '°{}liQ'fu~(.ce it 

possible to insert a cipher on the transmitted message of t'11~.t ma.ichine known 

as the Teletype and :nanu£actured by the Morkrum Company 1 Chicago, Illinois. 

The device is such that while the line impulses will thereby be in cipher a 

similar device at t.he receiving station will aul.omatically decipher the message and present a legible reproduct.ion. 

While this description will necessarily be restricted to a specific 

case of application it is desired to cover use of the same methods in aey 

telegraph system printing or !ianual,, over l~nes or by radio, using uriind.irect101"Jal currents for a.ctutation of instruments at a receiving station,, with or 

without distributing devices. 

With reference to .f'igure 1, a teletype transmitter is diagrammed in 

phase electrically with a tape transmitter. Means are provided for stepping 

forward the tape mechanism of the tape transmitter or trarumnitters by some 

such circuit as shown dotted under the co:rrl;rol at the proper time by the distributor. 

JP.gnat M, fi.gure 1,, is a differentially wound magnet,, the characteristic 

ot w·hich is that current of the same value in both windings se'IB up a core 

flux in opposition in each pertaining part of the ~ore which tends to neutralize each other and aram.ature 3 remain stationary. Current in one winding 

or the of.her individually will hot'1ever actuate armture 3. Mlgnet 3 my be 

directly placed on the Teletype nachine in place or the Teletype coils and 

print a local cipher message or may be used to actuate a cipher tape perforator which tape could be transmitted subsequently. 

With reference to figure 2,. A is a sending station and B is a receiving 

station. A Teletype transmitter is in phase electrically with a tape transmitter at the sending station. Again a tape transmitter is in phase with a 

receiying printer at the receiving station. A~ the sending station relay 6 

is controlled by the tape transmitter while relay 7 is controlled by the 

Teletype transmitter. The arnatures action· of these relays in joint operation 

with contacts wired as shown is a product ot both relays and therefore line 

continuity is a product of the action of the tape transmi~ter and the Teletype 

transmitter at any instant. 8 is Teletype receiver coils which will print 

a legible result of only the Teletype transmitters action. It will therefore 

be seen that in tl1!.nsmitting letter A (number one and two electrical impulse) 

with a cipher addition from the tape transmitter of say letter N (number three 

and four impulses,, contact, or pin, the line resultant through the differential coil' will be seen to be 

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@'pp roved for Release by NSA on 09-12-2013 pursuantto E .0. 1352a 
I • REF ID:A10502-

1 2 3 4 5 

Sanding + + 0 O O Teletype transmitting A 

0 0 + i- 0 Tape cipher transmitting N 

+ + + i- 0 Line resultant; K 

Now it shall be understood that at the receiving station a duplicate 

oipher tape is used in phase with the line resultant. Then 

Receiving 

1 2 3 4 5 

+ + + + O Line resultant K 

0 0 + + 0 Tape cipher N 

+ + 0 0 0 Resultant A 

Therefore an A has been transmitted and received while the line current 

may be anything other than an A. 

With re£erence to fi.gure3 1 it is desired to cover identical action in 

using a differential relay whose di.t'teren:t:.ial wimings are connected as shown 

tor the sending station a.nd rray be correctly used for the receiving station 

by having a similar connection with*l2 windings in the line circuit. 

Signllit 

Signed ~_,a~ .e "--' 

Signed 'W~~a..?J.~. . I